Details are explained in pine. Read the menus and help. You can create a file that is appended to every message you send. Typically this includes your real name, e-mail address, and optionally mailing address, phone number, mottos, jokes, funny little pictures made of characters, etc. Put in it exactly what you want to appear.
Attachments Read the information provided by pine.
E-mail correspondence is not as formal as paper correspondence. In fact, sending a sincere request for information to a famous and busy person often results in a speedy reply. But make it short and polite, and try to use correct spelling and grammar. A disadvantage of the speed and informality of e-mail is that sometimes you send off a scathing reply without thinking it over. Don't flame people, even if they deserve it.