How to Sign a PDF
Add your signature to a PDF without printing it, using Preview on Mac, Adobe Acrobat Reader on Windows, or Markup on iPhone, then save the signed file.
Someone sent a PDF that needs your signature. You can draw or photograph it once, place it on the page, and save the file, all with free built-in tools.
Open the Markup toolbar in Preview on Mac
Open the PDF in Preview and click the Markup button, the pen tip icon in the toolbar. If you do not see it, choose View, Show Markup Toolbar.
Create your signature
Click the Sign button, which looks like a scribble on a line, and choose Create Signature. Pick Trackpad and sign with your finger, Camera and hold a signature on white paper up to the webcam, or iPhone to draw it on your phone screen. Click Done. Preview stores the signature for future documents.
Place, resize, and save
Click the Sign button again and click your signature. It drops onto the page. Drag it to the signature line and pull a corner handle to resize. Choose File, Save or press Cmd + S. The signature is now part of the PDF.
Sign with Adobe Acrobat Reader on Windows
Open the PDF in the free Acrobat Reader. Choose Fill & Sign from the tools panel, click Sign yourself, then Add Signature. Choose Type, Draw, or Image to upload a photo of your signature, and click Apply. Click where the signature belongs, drag it into position, and choose File, Save.
Sign on iPhone
Open the PDF from Mail, Files, or Messages, and tap the Markup button, the pen tip icon. Tap the plus button in the bottom right and tap Signature. Draw your signature with a finger, tap Done, then drag it onto the line and pinch to resize. Tap Done again and save or reply with the signed file.
This is a drawn signature, not a digital certificate. Markup and Fill & Sign paste an image of your signature onto the page. For most everyday forms that is exactly what the sender expects. Certificate-based digital signatures, which cryptographically verify who signed and that nothing changed afterward, are a different feature. When a contract must be legally binding and auditable, use a service such as DocuSign or Adobe Sign when the other party requires it.
Flatten before sending if it matters. A signature added in Preview or Reader can sometimes be moved or deleted by the recipient. Printing the signed file to PDF, or exporting it, bakes the signature into the page.