A client can't log in to the app. What should I check?

Check in their file that the email is spelled correctly. It's their username for the app.

How do I move a client to another price tier?

In their file, Profile tab, Price tier block. From then on, they'll see the memberships of their new tier in the app.

Can I flag a client so they don't count in the statistics?

Yes. In Profile › Advanced, tick Exclude from reports. Useful for test or staff accounts.

I deleted a client by mistake. Can I get them back?

Yes, from the Recycle bin.

How do I invoice a minor whose parent pays?

In the client billing details, choose to bill their invoices to another client.