Minecraft Wiki:Userboxes

Userboxes are templates that users can create and add to their pages to give information about themselves.

To create a userbox, you can use the userbox template: Userbox. To add a userbox you have made to this page, put the userbox on its own page (you can do this in your own userspace or in the template userspace) and add  to the bottom of the section that best fits your userbox.