TechnoEsq has a great post in which he discusses the methods of signing electronic documents. As he explains:

Contracts are now signed electronically, emails are frequently used for communication between counsel and clients, pleadings in federal court are even electronically signed and filed. Obviously, such a paradigm shift is necessary in the modern era and makes today’s world work, from ATM and credit card purchases to purchasing automobile insurance online. From a legal perspective, however, there are many different forms of electronic signatures. The term is used interchangeably to describe three very distinct means of signing a document electronically:

1. Signature Stamp (or scanned version of a signature)

2. Electronic Signature (used in the federal court system)

3. Digital Signature (encryption used to authenticate a document).

This article explains the three forms of electronic signatures and assist in their creation.

I urge you to review this article to find out the uses for each of these three types of signatures as well as how to create and use each of them.