Wikipedia:Username Policy - Changing Your Username

Changing Your Username

Usernames can be changed by bureaucrats; requests should be made at Wikipedia:Changing username. User accounts with few or no edits might not be renamed, as it is quicker and easier to simply create a new account.

Once a username has been changed, existing contributions will be listed under the new name in page histories, diffs, logs, and user contributions. Signatures on discussion pages will continue to use the old name; while these can be changed manually, it is not recommended unless a contributor wishes to remove as much information as possible about their former name for privacy reasons. In such situations the old name will still be available in old versions of discussion pages. Username changes are listed in the user rename log.