Official Papers are an item you can buy from the Cubit Store for 2,500. They are used to change the name of a Realm. To use, go into the Overworld, stand by your Realm, select the Official Papers, and click (or tap) on your Realm. A box will come up, in which you can type your new fancy-shmancy Realm name. Whatever you do, do not name it "Sir Kewberth is a Smugglebottom", or you will be banned from the game. Permanently.