How do you write a professional non-email letter that is printed out and mailed through the post office?

I need to write a professional letter that I will print out and mail it in an envelope. I tried Googling but a lot of information is about email letters or addressing the envelope. Hardly any information about old-school letters. My questions are the following:After the printout, do I need to do a signature by pen?I remember in elementry school that my contact information needs to be in the top right corner of the letter, what type of information should I include there? Do you have any pictures as an example?What other etiquette is there to writing an old-school letter that is mailed physically?The ending of the letter, what should it be like? Is it: Regards, NAME HERE SIGNATURE orRegards, Signature NAME via /r/business http://ift.tt/2oss0PS