Hello
You need to have 25points and 15 posts before you can become a full member and can then change your profile picture , post pictures, have a signature, start new threads, edit posts , post links that show up correctly, and have quotes appear in grey boxes ,This thread explains about it.
https://forums.thesims.com/en_US/discussion/978073/new-members-guide-welcome-to-the-forums#latest