What type of mail can be forwarded with the usps and are there any things that cannot.?

Answer 1

1) All first class mail for 12 months. Mail is then returned to sender for the following six months with the sender receiving the new address attached. After 18 months all mail is returned UTF "Unable to forward."
2) Magazines for 6 months
3) All other mail that has an endorsement requesting forwarding is forwarded postage due based upon weight