In buying townhouses or condos, your new mailbox is generally in a bank of mailboxes and accessible only by key. If you're buying a bank owned home, you may never get the key to that mailbox...or even find out which mailbox is yours. And even if you get the key, you should change the lock. So how do you do that?
Take your fully signed, HUD-1 settlement statement, to your local post office. Present the statement to the clerk that helps you and explain that you would like your mailbox lock changed, or that you don't have access to your mailbox. The clerk will order the postal carrier to change the lock and present you with the key during the next mail delivery, or make other arrangements to have that lock changed and get you the key.
So all you need is that signed HUD-1 settlement statement and the address of your local post office. It's that simple!