Somebody has emailed you a PDF and asked you to "sign and return". There are four or five ways to do it, and the right one depends on your device, whether the PDF has form fields, and whether anyone might later need proof that you were the one who signed.
The quickest way on any device: a browser tool
A browser-based signing tool works the same on a laptop, an iPhone or an Android phone, with nothing to install.
- Open the Sign PDF tool and choose your file.
- Create your signature: draw it with a finger or mouse, type your name, or upload a picture of your handwritten signature.
- Tap the page where the signature goes, and add the date beside it if the document asks for one.
- Download the signed copy and send it back.
Check whether the tool uploads your file. Many online PDF tools process documents on their servers; the Salsox tools run inside your browser, so the PDF never leaves your device. For a contract with your address, salary or ID number on it, that is worth knowing.
On a Mac: Preview
Preview, which comes with macOS, can sign PDFs. Open the file, click the Markup toolbar button, choose the signature icon and create a signature with the trackpad, the camera (by holding a signed piece of paper up to it) or an iPhone. Drag the signature into place and save. Preview stores signatures for reuse, which is convenient on your own computer and something to clear if you use a shared one.
On an iPhone or iPad: Markup
Open the PDF from Mail or the Files app, tap the Markup icon, then the plus button and Signature. Sign with your finger, place it and tap Done. The signed file replaces the original in Files, so duplicate it first if you want to keep an unsigned copy.
On Android
Android has no single built-in equivalent; it depends on the phone maker and the PDF apps installed. The browser method above is the most reliable option across devices.
When the PDF is a form
Some PDFs have boxes you can type into. Others are scans of paper forms, with nothing to click. Either way, fill in the answers before you sign:
- For a fillable form, the Fill and sign PDF tool lists the form's own fields so you can complete them, then adds your signature.
- For a scanned form, place text, dates and checkmarks on the printed lines yourself.
Download a flattened copy, which turns your answers into part of the page so they cannot be changed afterwards. Most offices prefer it.
Initialling every page
Long contracts often ask for initials on each page. Doing that one page at a time is slow. The Add signature to PDF tool places your initials on page one and repeats them at the same spot on every page in one step.
When signing your own copy is not enough
Everything above produces a signed file. It does not produce evidence. If you are the one collecting signatures, or the agreement matters enough that someone might later dispute who signed, use a signing workflow instead: each person gets their own link, and the system records who opened and signed the document, when and from where. The request a signature tool prepares one, and the guide to sending a document for signature walks through it.
A note on what kind of signature this is
Drawing or typing your name on a PDF creates an electronic signature. That is different from a digital signature, a certificate-based seal that PDF readers check for tampering. Both have their uses; the article on electronic versus digital signatures explains the difference.
Frequently asked questions
How do I sign a PDF for free?
Open it in a free browser tool such as Sign PDF, draw or type your signature, place it and download the result. Preview on a Mac and the markup tools on iPhone and Android also work without paying.
How do I sign a PDF on my phone?
Use a browser-based signing tool, which works the same on iPhone and Android, or the Markup feature in the Files app on iPhone. Sign with your finger, place the signature and save or share the file.
Is a signature I add myself legally binding?
It can be, since many laws accept electronic signatures for ordinary contracts. But a file you signed yourself records nothing about who signed or when. If proof might matter, sign through a workflow that keeps an audit trail.