I've read in the forum that you stick "copyright:" in front of the intended name, but when I tried it, it still appears as a regular tag. What should I do?
Which tag(s) are you trying to change into copyright tags? Also worth noting, only Builders and up can change the types on tags with more than 50 posts (as per help:users). The method you describe would work, again subject to the post count limit for the tag.