The Ready to Review status appears when work is completed on a client ticket and Auto-Approve is disabled. In this case, the ticket stays in Ready to Review until the client manually approves it.
When does this status appear?
When a work is completed on a ticket, and
Auto-Approve is turned off for that client
When does this status not appear?
When Auto-Approve is enabled, in that case, tickets go straight to Closed once the work is completed.
You can check the Auto-Approve setting by going to Clients --> opening a specific client's page --> navigating to the Ticket Settings tab. There, you'll see an option called Auto-Approve.