How do i change my signature?

[h4mza]

I cannot find the option in User CP, and when i click on my username, i get

h4mza, you do not have permission to access this page. This could be due to one of several reasons:

1. Your user account may not have sufficient privileges to access this page. Are you trying to edit someone else's post, access administrative features or some other privileged system?
2. If you are trying to post, the administrator may have disabled your account, or it may be awaiting activation.

I also never got an activiation email