How do I sign a PDF on an iPhone?

Open the PDF, tap the Markup button, tap the Add button, then tap Add Signature. Sign with your finger, tap Done, then drag the signature into place and drag a dot on its outline to resize it. These are the steps on Apple's iOS 26 and 27 pages, which word the dot slightly differently.

Can I sign a PDF I received by email?

Yes. Apple's Mail page covers drawing on the attachment, and its Markup page says the plus button adds a signature. A second route, on iOS 27, is tapping Preview in the attachment's toolbar, filling out or annotating the PDF there, and attaching it to a reply (see Mail above).

Do I need to install an app?

Apple's pages use apps that come with iPhone, such as Mail, Notes, Photos and Preview.

How do I sign a document that is not a PDF?

Apple says that in supported apps such as Notes and Photos, you can use the Markup tools to add your signature to images and documents. We did not cover Word or Pages files.

How do I delete or redo a saved signature?

To redo one while making it, tap Clear and sign again. To delete one, tap Markup, the Add button, Add Signature, then Add or Remove Signature, and tap the Delete button next to it. Rotating your iPhone gives you more room to sign.

Is a signature made on iPhone legally valid?

For any transaction in or affecting interstate or foreign commerce, US federal law says a signature cannot be denied legal effect solely because it is electronic. Wills, family law and some notices are excluded. We are not lawyers, so check your own case.

How do I get someone else to sign a PDF?

Markup signs only your own copy. Send the PDF through a tool that collects the signature: Dropbox Sign (three free requests a month), DocuSign (free to sign, a trial to send), Adobe (two requests every 30 days on a free account) or a Loop link from a Mac.

How much does Loop cost?

Loop has a 14-day free trial, then costs $49 once for one person, with no yearly fee. The sender needs a Mac, and the person signing types their full name. We have not tested signing on a phone.

Where do the prices and facts on this page come from?

From Apple's iPhone User Guide pages for iOS 26 and 27 on signing documents , annotating attachments in Mail , replying with a PDF in Preview and filling out forms in Preview , plus Apple's Markup and scanning pages, published 25 March and 13 February 2026. The iPhone User Guide pages show no updated date. We also used Dropbox , DocuSign , Adobe , Cloudflare and the text of the ESIGN Act on govinfo.gov. We read all of them on 2 November 2026, except Adobe's archived copy of 13 October. We did not tap through these steps on an iPhone, so Apple's pages are the source. We could not confirm what Markup does to the PDF, whether signatures sync between devices, whether Preview is on iPhones running iOS 18 or 17, DocuSign's trial length, or whether Loop's signing page works on a phone. Prices are in US dollars for one person. We could not confirm whether tax is included in the prices.

How to Sign a PDF on iPhone: Mail, Files or Preview

Quick Answer

Your iPhone can sign a PDF with apps that come with it, such as Mail, Notes and Preview, and Files is where a saved PDF opens. Apple's iPhone User Guide says to tap Add Signature, sign your name with your finger, tap Done, then drag the signature where you want it. That signs your own copy. If another person has to sign, Markup cannot send it for them.

Your PDF	Open it in	Section
Came by email	Mail	Mail
Saved on iPhone	Files	Files
A form to fill	Preview	Preview
Printed on paper	Notes	Paper Forms
Someone else signs	A signing tool	Someone Else Signs

We read Apple's pages for iOS 27 and iOS 26 on 2 November 2026 and did not tap through the steps on an iPhone, so the steps below are Apple's, not ours. Apple's guide also has iOS 18 and iOS 17 versions, which we did not read, so an older iPhone may differ. These steps cover an iPhone. We did not cover Android, an iPad or Word and Pages files, so this page does not answer those.

Mail

Apple describes two routes for a PDF that arrived by email on iOS 27.

Sign it in place. Apple's Mail page says to open Mail, tap the attachment in the message, then tap Markup. That page lists only drawing tools and does not mention a signature. For the signature, use the Markup toolbar steps on Apple's signing page: tap the Add button, then Add Signature. When you are finished, tap Done. Apple's Mail page says you then choose to reply to the attachment sender, start a new message, save the annotated attachment to your files, or discard your edited attachment.

Fill it in Preview, then reply. Apple's page on replying with a PDF in Preview gives these steps:

Open the email, then tap the attachment to view it.
Tap Preview in the toolbar to open it in the Preview app.
Fill out or annotate the PDF.
Go back to Mail and open the original email.
Tap the Reply button, tap the Attachment button, then tap Attach File.
Select the updated PDF, optionally add text, then tap the Send button.

For a message you are writing, Apple's Markup page says to tap the attachment, tap the gray arrow icon, tap the Markup button, then tap the plus button to add a signature, text and more. Apple's pages do not say which route to prefer. The first keeps you in Mail, and the second gives you Preview's form tools.

Files

Use this when the PDF is saved on your iPhone. These steps are combined from two sections of Apple's signing page for iOS 27: opening and finishing come from its form-filling section, and the signature steps come from its Markup section.

Open the PDF. If prompted, open it in the Files app, then tap Save.
Tap the Markup button. In the Markup toolbar, tap the Add button, then tap Add Signature. Apple's Markup page also calls the Add button the plus button.
Tap a signature you saved before, or make a new one (see Saved Signatures).
Sign your name with your finger, then tap Done.
Drag the signature where you want it. To resize it, drag a dot on its outline (iOS 27 calls it a blue dot along its bounding box).
Tap the Menu button, then tap Export, Print or the Share button. Tap the Back button to save it.

Apple's form-filling steps go straight to the Add button without a Markup step, so on a form you may not need step 2's first tap.

The iOS 26 version of the same page ends differently. Instead of the Menu button, you tap the Share button to send the signed file with Mail, Messages or AirDrop, then tap Done to close the document.

Preview

Apple's iPhone guide describes the Preview app for iOS 26 and iOS 27, with the same text for both. We did not check iOS 18 or iOS 17.

To fill in a form:

Open the Preview app and open the PDF form.
Tap the Form Filling button.
Tap a field and type, or tap the AutoFill suggestion above the keyboard.
To add a signature or a text form box, tap the Add button.

To sign a PDF that is not a form, Apple's annotate page says to open it in Preview, tap Markup, tap Add, then choose an option such as a sticker, signature, shape or text.

Paper Forms

If the form is on paper, Notes can scan it and sign it. Apple's scanning page, published 13 February 2026, gives the steps.

In Notes, open or create a note, tap the Attachment button, then tap Scan Documents. (In the Files app, tap the More button, then Scan Documents, but the signing steps below are Apple's Notes steps only.)
Tap the scanned document in the note, then tap Markup.
Tap Add, then tap Signature, and choose a saved signature or create a new one.
Adjust the size of the signature box, place it, then tap Done.

This page says Signature, where the iPhone User Guide says Add Signature. We quote each page as it is written.

Saved Signatures

Apple says that after you create a signature, iPhone saves it for the next time you add one with Markup. You can keep several, such as a nickname or initials. These steps are for iOS 27:

Redo it. Tap Clear, then sign again.
Get more room. Apple's tip is to rotate your iPhone to have more space to sign.
Label it. Tap the Menu button next to New Signature, then pick a label such as given name, nickname or initials. On iOS 26 Apple says to tap the arrow next to New Signature instead.
Add another. If you already have one, tap Add or Remove Signature, then tap the Add button.
Delete one. Tap Add or Remove Signature, tap the Delete button next to the signature, then tap Done.

To undo a mistake while placing it, Apple's Markup page says to tap the Undo button, and that shaking your device lets you tap Redo. Apple's pages say nothing we could find about signatures reaching your other devices, so we do not say they do.

Someone Else Signs

Markup signs the copy on your iPhone. To have another person sign, send the PDF through a tool that collects the signature. Each allowance below is on the vendor's own page.

Dropbox Sign. Dropbox says all Dropbox customers can send up to three free signature requests per month. Its signer page says signers do not need to create a Dropbox Sign account.
DocuSign. DocuSign says a free account can sign, return and store as many documents as you want. Sending starts with a trial, and we could not confirm its length.
Adobe. Adobe's page says a free account gets two request e-signatures transactions every 30 days, from an archived copy of 13 October 2026.

We did not read these pages for what the person signing sees on an iPhone, so we do not say how each works on one. For all eight tools and the catches, see our free e-signature comparison.

Loop

Loop is the wrong tool for signing a PDF you were sent. Markup does that for free. Loop fits one case: you work on a Mac and someone else has to sign a PDF, in a link under your own name.

Drop the PDF on the Loop icon in the menu bar.
Turn on Require Signature in the link's settings, and place up to 12 Sign Here spots.
Paste the link into your own email. Loop does not send it.
The signer opens the link, enters an email address, types their full name in Your Full Name and presses Sign.
Download Signed Copy. You get a PDF of every page with the signature where it was placed, then a record page.

Loop runs on a Mac, so you cannot make the link from an iPhone. The signer types a name, with no drawn signature. We have not tested signing on a phone: our signing tests run in a desktop browser. So we do not say a phone reader can sign, and if yours will use one, make a test link with the 14-day trial and open it on your own phone first.

Try Loop free for 14 days

Your own branded link, with notes on the exact second. $49 once.

Download for Mac

Limits

Markup puts your signature on the page as you drew it. Apple's pages describe signing with your finger and placing it. They do not describe a record of who signed or when, a certificate, or what is stored in the PDF.
Markup signs your own copy. It does not send the PDF to anyone to sign.
Loop is Mac only on your side, and it does not sign a PDF you were sent.
Loop's signature is a typed name. The email is checked for format only, and Loop does not check identity with an ID check, text-message code or certificate.
Loop does not hold the file back until signed. Signing is a request on the page, not a lock.
Loop does not send the email, and it is not free after the 14-day trial.

The Law

For any transaction in or affecting interstate or foreign commerce, 15 U.S.C. 7001 says a signature cannot be denied legal effect or enforceability solely because it is in electronic form. Some documents are excluded under section 7003, including wills, family law, court orders and certain notices, such as utility cancellation or default, foreclosure or eviction notices tied to a credit or rental agreement for a primary residence. We are not lawyers, and this is not legal advice. Our free e-signature comparison has the longer version.

Cost

None of the Apple pages we read mentions a charge for these steps. Loop is $49 once for one person.

A signed PDF sent through Loop sits in your own Cloudflare account, and the first 10 GB there costs nothing. If you store more, Cloudflare charges you; its pricing page, updated 30 October 2026, shows $0.015 per GB-month and nothing for downloads. Switching storage on may make Cloudflare ask for a card.

To try a signing link on your own phone, the 14-day trial begins the first time you open Loop, and you pay nothing to start. Until you buy a licence, the page your signer opens carries a small "Shared with Loop" badge.