This question relates to tags, the words or phrases which describe the topic of a Server Fault questions.
A tag is a word or phrase that describes the topic of the question. Tags are a means of connecting experts with questions they will be able to answer by sorting questions into specific, well-defined categories. See Help Center > Asking: What are tags, and how should I use them?.
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.