I'm doing it by mail. I don't know wha you mean by letterhead..? I'm a newbie. Here's what I am going to do:
1. Print out sheet from interfolio
2. Have envelope ready to send to interfolio.
3. Get The writer to sign it and stamp it ( or whatever I need to do)
4. Write my AACOMAS and amcas ID on that same letter
5. Mail the letter to interfolio
Does this look okay? I'm sick of the confusion lol