How to add users?

This is a really simple question – how do I add users?

In a project, I can invite a (completely) new user using their email address, and it sends them an invitation. This then leads to a sign in page that says “To accept this invitation, sign in” - but they can’t sign in because they have no account yet. There is a “forgot password” link, but that’s not usable because the account doesn’t exist.

How do I resolve this chicken & egg problem?

Never mind. I figured out that you have to create the user beforehand – I don’t have registration enabled. What’s confusing is that sending group invitations is completely disconnected from whether users actually exist, so you’re entirely free to send invitations to people who are not on the system – but it provides no way of allowing them to sign up (if you have open registration disabled), leaving them in limbo…