For either your club or to promote your content elsewhere?
Advertising
It is fine to promote your club on your profile page , blog, another club (only if you get explicit permission from the owner and club doesn't usually get posts with adverts) or the clubs and teams section. Anywhere else, and the kids begin to report you for spamming adverts. Chess.com live tournaments, PMs, chat messages, Chess University and anywhere else with kids is a big no. This what Chess.com says - https://support.chess.com/article/329-how-do-i-invite-someone-to-join-my-club
If you need help, please contact our Help and Support team.
Is there a chess.com rule against advertising for a club with a blog post?