Every logged-in user has a user page. (For example, if your login name is "MyNick", your user page will have the title "User:MyNick".)
You can find your user page with the link at the top of every page, or by following this link. Most people use user pages to give information about themselves and their interests and keep links to useful things.
You can make your user page as simple or as complicated as you like. You can add formatting or color with wiki markup or with HTML, or leave it plain and simple. You can also add pictures, either a picture of yourself, one that expresses something about you, or just one you like. However, all pictures added to Croc Wiki must be free-use.
You may not use your user page for any content that is prohibited on the wiki or Miraheze at large. This includes copyright violations, pornography, excessive advertising, promotion of illegal activities, and hate speech. Aside from this, users are generally allowed to do whatever they would like with their user pages.
Editing user pages
User pages are still wiki pages, so they are open for everyone to edit. Most people will ask before making major changes to someone else's user page though. Small changes, like formatting fixes or spelling corrections, are absolutely fine, and can be done freely - it's always nice to find your user page improved.