Signing on the Dotted Line in Preview
With your Mac and the Preview app, instead of printing a document, signing it, and then either faxing it back to the person — or scanning it and then returning it by e-mail — you can sign it directly on your Mac. You can use it on contracts and W-9 forms — any PDF file. Follow these steps:
Download the document you need to sign from a website to your Downloads folder, or drag an attachment from an e-mail you received to the Desktop.
Click the Launchpad icon on the Dock and then click the Preview icon.
Choose File→Open and then select your document from the Downloads folder or Desktop.
Choose Tools→Annotate→Signature→Create Signature from FaceTime Camera.
The Signature Capture window opens.
Sign your name on a blank white piece of paper.
An index card works well.
Hold the paper up to the FaceTime camera and align your signature on the blue line.
It will be backward in the viewer but correct in the preview.
Move the paper closer or farther away from the camera until the size and position is right and then click Accept.
Click the signature line on the document.
Your signature is pasted into the document. Click and drag the signature to better position it; click and drag the corners to resize it.