Insert your poster, the LOR, the return address labels and the return postage in a wax envelope provided by the USPS inside the poster tube and if you are mailing it priority mail they can tape the open end up for you; if you are mailing it regular mail bring your own tape to seal the open end.
hope this helps
hint: poster tubes are rarely sent to celebrities and they tend to stand out (pun intended). If too much time has elapsed feel free to call the address where you sent it and they should be able to spin around in the chair and see it awaiting the celebrity or the PA to pick it up.

Hi,
I was wondering how easy is it to send a poster in a tube to someone to sign? Is it easy for them to sign and return? How would you pay for the postage for the way back?
Thanks,