You probably don’t. It does not matter anyway. You can’t DO anything with it besides be green.
The WoW Community MVP program has not been active since the last recruitment back in 2018 under Ythisens the yak. Eventually most of those folks have sort of moved on. There is the Community Council program with yellow text that you can apply for once a year and hope to get accepted. If they are doing it still. Not sure they are going to keep that running or not.
The main MVP program I am in Tech/Customer Support which you spend years posting and generally being helpful with information. They MIGHT notice you and then they MIGHT decide there is an opening in the program and ask if you want to be a tech/customer support MVP. That is super rare and there are very few people in the program. The ones that are, are selected from across the Blizzard forums, not just WoW. I was invited in 2013 as the primary person helping on the D3 TS forums, esp with CS related topics.
You can read more about the Community MVP program in the pinned sticky at the top of the forums. Scroll towards the end of it.
The Community Council is discussed here
Applications were last done in 2023
The Council Forum is here where any interactions between the Devs and Council are transparent.