To create a new tag, either:

 * Add it as a tag on a _new_ question, or
 * Edit an _existing_ question to include the new tag.

In either case, [creating a new tag][1] requires 300 reputation.

Once the tag is created this way, you can then edit it to include an excerpt and tag wiki entry.


  [1]: https://serverfault.com/help/privileges/create-tags