We are in an era of an almost paperless office. When letters and other documents are sent in PDF format over email, the signature follows as a digital format. There are several ways of sending a file with your digital signature in it. The quickest way is to actually printout the page, sign it and scan it back as a PDF. While it may be quick, it may not be the nicest looking method.
Another method, which I have done, is sign my signature with a thick marker on a white piece of paper, scan it and clean it up using Photoshop. It might be time consuming at first but once you have it as an image file, you can just add it as an image in just about any file that you want. Other software can even provide a more secure way of signing. Adobe Acrobat Pro can create verifiable digital signatures for you. However, these software are not exactly free; you need to shell out some money for them.
Digital Signature in Preview
It’s a good thing that OS X now has a great new feature. It now has a built in signature scanner that makes the method that I use, described above, a much easier process. To scan your signature, open up Preview and look for your Annotations. Select Create Signature From Built-In iSight. Sign a blank piece of white paper with some black ink and hold it up against your built-in iSight camera. Use the guides provided. Once aligned, capture your signature. You now have your signature on file. Preview can store multiple signature so you can scan your full signature and the shorter one you use for initialling something.
This is an easy and fast way to create a digital signature in Preview.