How to sign a PDF without printing it

Two kinds of electronic signature

"Signing a PDF" can mean two different things, and it helps to know which one you're being asked for.

• A visual signature is an image of your signature placed on the page — drawn with a finger, mouse or trackpad, or typed in a handwriting-style font. It looks like a signature on paper and is accepted for many everyday documents: rental forms, school permissions, delivery notes, freelance agreements.
• A certificate-based digital signature is cryptographic. It's issued through a signature service that verifies who you are, and it proves the document hasn't changed since signing. Some contracts, government filings and regulated industries require this kind.

The tools in this guide create visual signatures. If the person asking for your signature names a specific signing service, or the document says a qualified or certified electronic signature is required, use that instead. Rules differ between countries and organisations, so when in doubt, ask the recipient what they accept.

Step 1: fill in the form, if there is one

Many PDFs from banks, schools and government offices are fillable forms with boxes you can type into. Fill PDF Form lists every field — text boxes, checkboxes, dropdowns and option buttons — so you can complete them and save a filled copy.

If the PDF has no fillable fields, the tool tells you. You can still sign it; for text you need to add, a printed form like this is best completed in the program that created it, or you can ask the sender for a fillable version.

Step 2: add your signature

1. Open Sign PDF and add the document (the filled copy, if you just completed a form).
2. Draw your signature, or type your name to set it in a handwriting-style font, and pick an ink colour.
3. Choose the page, drag the signature onto the signature line and adjust its size.
4. Click Sign and download the signed PDF.

Each run places one signature on one page. If you need to sign or initial several pages, run the signed file through the tool again for each one.

Step 3: lock the answers

A filled-in form keeps its fields editable, so anyone who receives it could change an answer, and some viewers display form fields differently. Flattening draws every field's current value onto the page and removes the field, so the document looks the same everywhere and can't be casually edited.

You can flatten while filling — tick Lock answers (flatten) in Fill PDF Form — or afterwards with Flatten PDF. Keep an unflattened copy if you might need to change an answer later; a flattened copy can't be turned back.

Good habits for signed documents

• Read the final file before sending it: check the signature is on the right line and every page is there.
• Keep a copy of exactly what you signed and sent.
• Protect sensitive documents. A signed contract with personal details deserves an open password if it's travelling by email — see PDF passwords explained and Protect PDF.
• Watch the file size. Signing doesn't make a PDF much bigger, but scanned forms are often large already; Compress PDF helps if an upload form rejects it.

Why not print, sign and scan?

A scanned page is a picture of the document, so the text stops being searchable, the file grows to several times its original size and small print gets harder to read. Signing digitally keeps the original text intact and sharp, and takes a minute instead of a trip to the printer.