How to sign a PDF on iPhone, Android, Mac and Windows

Somebody has emailed you a PDF and asked you to "sign and send back". You do not have a printer, and you are not going to buy software for one form. You do not need to: every major operating system can do this, some of them very well, and where the built-in option is poor there is a free tool that runs in the browser.

Menus and icons move between versions, so treat the steps below as directions rather than a script. The shape of each route has been stable for years.

On an iPhone or iPad

Apple's Markup tools are built into the Files app, Mail and Photos, and they handle PDFs properly.

1. 1

   Open the PDF

   If it arrived by email, tap the attachment in Mail. Otherwise save it to Files and open it from there.

2. 2

   Turn on Markup

   Tap the Markup button — a pen tip, usually at the top or bottom of the screen.

3. 3

   Add a signature

   Tap the plus button and choose Add Signature. The first time, you draw it with your finger; after that it is saved and offered again.

4. 4

   Place it and finish

   Drag the signature into position, pull a corner to resize it, then tap Done. In Mail, the signed copy goes into a reply; in Files, it saves over the original, so duplicate the file first if you want to keep a clean copy.

The same Plus menu adds text boxes for a printed name or a date. If the PDF has real form fields, recent versions of iOS will also let you tap into them and type.

On a Mac

Preview, which opens PDFs by default, has the best built-in signing of any desktop system.

1. 1

   Open the PDF in Preview

   Double-click it, or right-click and choose Open With, then Preview.

2. 2

   Show the Markup toolbar

   Click the pen-tip button in the toolbar, or use View, then Show Markup Toolbar.

3. 3

   Create a signature

   Click the Sign button. You can sign on the trackpad with a finger, hold a signature written on white paper up to the camera, or draw it on an iPhone or iPad signed in to the same Apple account.

4. 4

   Place it and save

   Choose the signature, drag it where it belongs, resize it, and save. Use File, then Export as PDF if you want a separate signed copy.

On Android

Android has no single PDF viewer that every phone ships with, so there is no single answer. What you have depends on who made the phone and which apps are installed.

• Google Drive opens PDFs with an annotation pen on most current phones. You can draw a signature, but it is freehand ink rather than a reusable signature you can place and resize.
• Samsung phones can open a PDF in Samsung Notes and write on it with a finger or the S Pen, then share it back out as a PDF.
• Adobe Acrobat Reader is a free download with a Fill and Sign feature that stores a signature and places it properly, at the cost of an app and an Adobe sign-in.

If none of those suits you, the browser tool described below works on any Android phone with Chrome.

On Windows

Windows has nothing equivalent to Preview. The closest built-in option is Microsoft Edge, which is the default PDF viewer on most Windows machines: open the PDF in Edge, choose Draw, and sign with a mouse, a trackpad or a pen. It works, but the result is freehand ink — you cannot save a signature to reuse, and drawing a legible one with a mouse is harder than it sounds. Edge's Add text tool will put your printed name and the date beside it.

The other common route is Adobe Acrobat Reader's free Fill and Sign, which handles it well but means installing Acrobat.

Anywhere: the free sign-PDF tool

We built a free PDF signing tool for the cases above where the built-in option is awkward — a Windows laptop with a mouse, an Android phone with no good viewer, a borrowed machine where you would rather not install anything. It runs in any modern browser, at desktop or phone width.

1. 1

   Open the PDF

   Drop it on the page or choose it from your files. It opens in that browser tab: the file is read by code running on your device and is never uploaded to us or anybody else.

2. 2

   Create your signature

   Draw it with a mouse, trackpad or finger, or type your name and pick a handwriting style.

3. 3

   Place it

   Tap where it goes, drag it into position and pull the corner to size it. Add today's date, which you can edit, or a line of text such as your printed name or title, the same way.

4. 4

   Download

   The signature, date and text are written into the PDF itself and the file downloads to your device.

There is no account, no email address, no watermark and no limit on how many files you sign. The one thing it will not open is a password-protected PDF; remove the password in your PDF reader first. Scanned documents and rotated pages work.

Drawn or typed: does it matter?

Not legally. Under US law, and under eIDAS for a simple electronic signature, a typed name in a handwriting font is as much a signature as one drawn with a finger, provided you meant it as one. The difference is practical. A drawn signature looks like the one on your passport, which reassures some recipients; a typed one is legible and quick on a laptop with no touchscreen. Use whichever the other side is less likely to query, and use the same one each time you sign for the same organisation.

A few things that trip people up

• Fill the form fields before you sign. Some PDF readers lock or flatten a file once a signature is added, and the fields stop accepting input.
• Check the page you placed it on. On a long agreement the signature line is usually on the last page, and initials may be wanted on every page. Read the document for "initial here" before you send it back.
• Keep the original. Several of the routes above save over the file. A clean, unsigned copy costs nothing and saves an awkward email.
• Send the PDF back, not a screenshot. A photo of a signed page loses the text layer and is harder for the other side to file.

When a picture of your signature is not enough

Everything above does the same thing: it puts a picture of your signature on the page. That is how a great many documents are signed every day, and for a form going back to somebody who asked for it, it is usually fine.

What it does not do is record anything. There is no evidence of who placed the signature, when, from which device, whether they consented to signing electronically, or whether the file has been edited since. For a form, nobody will ask. For an agreement that might one day be disputed, those are exactly the questions that get asked — and the answers are what make an electronic signature hold up, as we explain in what makes an electronic signature binding. Whether e-signatures are valid at all for your kind of document is covered in are electronic signatures legally binding.

If you are the one who needs somebody else to sign, send it from XDocs instead. Upload the PDF and drag the fields onto it, or start from an agreement template with the signature blocks already in place. The other side signs in their browser with no account; every view, consent and signature goes into an audit trail; and everybody gets the signed PDF with a certificate of completion. The free plan includes 5 sends a month, with no card.