Most theatre you need to be part of some kind of membership, but I just want to be part of the kind of theatre where I walk in, audition, and if they like me they take me and I do what I can. Thanks!
If you’re talking about big, professional theatre, Mirvish sometimes holds open calls for non-equity performers. Their website is mirvish.com and has audition updates on it. Otherwise, I’d say check out local community theatres if you just want to perform for fun