Hi:
Your request should include the following;
1. A sincere Letter Of Request (LOR) asking for the person's autograph.
2. The item that you are requesting to be signed.
3. A Self Addressed Stamped Envelope (SASE) with your address on it. The postage on this envelope must be enough to get your item back to you. Put your item in it and have the post office weigh it and put the postage on this envelope. Remove your item from the SASE.
3. Put you letter of request (LOR) the SASE and your item in the envelope with the address of the person you are sending your request to. Have the post office weight everything and add postage to this envelope.

One envelope (sending) should be large enough to send everything to the person you are asking for the autograph from. The SASE, the (returning) envelope should be big enough to return your item to you.

Hope this answers your question.

do just send just a letter in a c6 0r c5 with envelope ?