If you see a need for a new tag, consult Help Center > Privileges > create tags. There is advice there on evaluating if the proposed tag is appropriate to add. Create the tag by adding it to a question. To do this, you need to have the Create Tags privilege, which is awarded at 300 reputation on Server Fault. If you do not have this much reputation, post a question on Meta Server Fault asking someone else to create it.
Some questions about how to use Server Fault are asked and answered on Meta Server Fault. But there is more information in the Help Center. Searches in Meta Server Fault don't return results in the Help Center. You can find the Help Center via the link [Help] in the lower-left of Server Fault pages.
[tags]to the Help Center content will improve this situation.