A signature is typically just someone's name written in a stylised manner. However, this isn't strictly essential. All that is required is a mark that represents you. Anything that marks the paper can be used to make the signature. You could use just about any kind of symbol or word as long as it is easily recognised as yours. For example, if you were willing to put your name on hundreds of documents every year then you could use your own name as a signature. Or, you could use an abbreviation for yourself, or even a phrase. As long as it is unique it will do. Just make sure that you don't sign anything you wouldn't be happy to be associated with in some way. In most cases a space of two lines is enough width for your signature. If you want to include more than this in some letters then they should be written on separate sheets of paper and joined together later. This may not seem like a big deal but many people find it difficult to write anything other than their name on every document they send out. It is up to you how formal you want your correspondence to be but including a phone number or email address as well as your name will help others identify who they are dealing with. You only need to write your name once at the beginning of each document but it can appear anywhere within the text if relevant.