I remember back in the day a post from jagex, invited to by a Pmod with some formulary. The time changed a lot and i try to find the formulary but i can't find it, i have played for a while almost 15 years. i would like to participate a Pmods team.
Player moderators are individually selected by Jagex based on several factors, but they do not accept requests or applications. If you'd like to read more about player moderators, check out the Player Moderators sticky in the Community Home forum, as well as the Moderators and Community Helpers support article. These resources explain more about the role and the selection processes.
The best advice I can give is to be a player first and enjoy the game while being a positive participant in the RuneScape community. It is important to remember that any player has the ability to be an asset to the community, even if they aren't a player moderator.
So have fun, be yourself, and game on! Jagex is always looking and watching for who they're going to recruit next.