Notifications: MS Teams and more

I see Microsoft Teams as one of the possible notification channels… how does that work?

There’s many others, most of which I don’t know. The email is fine and works, but are there other -simple- (free?) ways of alerting? Can I send TEXT messages too?
Any plugins / extensions that might add more capabilities here.
Sorry for all the questions… trying to understand this space a bit…

Anyone who could help me here?