If a tenant attends an AGM can they participate in discussions or only participate if they are invited.
Who’s going to stop them?
A formal option: Since a general meeting is a meeting of owners, I would think the chair could rule on whether someone has standing at the meeting. In the ACT at least, an owner can appoint anyone (except the strata manager) to be their proxy, so, here at least, I would advise a tenant who wishes to take part in an AGM, including voting, to suggest to the owner of the unit that they be appointed as the owner’s proxy.
An informal option: That said, a reasonable chair would, I think, allow anyone to speak if they are contributing something worthwhile to the discussion of the agenda item at hand. You could speak to the chair ahead of the meeting to alert them to your desire to speak on some topic during the meeting.