Ways to Green Card
Getting Green Card
Sample USCIS Envelope Containing Green Card - Permanent Resident Card
This is a sample of the envelope that carried the green card (permanent resident card). This sample is shown to show that it is just the standard envelope. It does not have any special markings such as "Do NOT Forward" contrary to popular belief.
Therefore, if you changed your address since you became permanent resident and provided the change of address with the post office, post office would forward that envelope to you.
However, you are still required to file Form AR-11, Change of Address with USCIS.