First of all, you have to have a graphic program on your computer. Most of us use Photoshop which is expensive to buy, although you can download a free trial version on the Adobe website to see if you like it. You can also use Photoshop Elements, which is basically Photoshop Lite, and it's around $100 give or take a bit, I think you can also download a trial version of that at Adobe as well. Also, you can also try Paint Shop Pro, which is about the same price as Photoshop Elements. You used to be able to download trials of Paint Shop Pro as well from the Jasc site, now that they are owned by Corel, I'm not sure, but would certainly check it out and see. There are also several free graphics programs you can download from the Internet. I'd say the best one of those is The Gimp. The Gimp basically works like Photoshop, but I don't find it as user friendly, or as easy to work with. However, for a free program, it's an amazing program. I just found it hard to work with, and hard to get the hang of it. I know a lot of real computer Geeks swear by it. I swear by Photoshop, so I couldn't really deal with The Gimp, when I had it on the computer.
There are some other free programs as well, and I don't know the names of them, but they're out there, and I think they're a lot easier to use than The Gimp.
Icklemiss does have a tutorial on this thread on how to make a signature. It's very easy to understand, and it's more about how to make a basic signature. It's for Photoshop, but if you use Paint Shop Pro, or even The Gimp, you should be able to follow it and get the same basic idea on how to make a signature. Here is the link to her Tutorial.http://www.freewebs.com/icklemiss21/index.htm