Is it okay to write: “I have enclosed a self-addressed stamped envelope to facilitate your response.“ or is there a better, similar sentence?

How do you ask someone in a polite way if they could sign two items that you send along with your letter?

Hey there! :-) I want to send a letter from Germany to the US and I have a few questions... 1. Is it correct that the address on the envelopes must be written in capital letters and that no punctuation is allowed? 2. How do you start your letter? I want to write to an actor who is just a couple of y...