Signatures is the bottom portion that will show up in every post you make. If you look at my post, my signature is that gif of Smash Bros and a picture of Kirito from Sword Art Online. You can edit your signature by going to your settings and looking on the left side of the screen where it says settings and one should say edit signature. If you want, there are lots of users who make signatures for others if you request them! Good luck in everything! :3