Hi Cindy,

Thank you for your interest in our plugin.

Yes, Amelia has option to set maximum capacity for each service and each event. Depending on what you need you can create services or events. The main difference is that for services customer can choose one of the available dates and time slots in the calendar (customer on the form choose services and employee if there are multiple of them, or just sees calendar if you have just one service and employee), and for events you define date and time and customer can just book it like purchasing a ticket. Like I said both can have maximum capacity set and once the maximum is reached that time slot for services or that event becomes closed. 

As for the reservations that are taken by phone you can add on the back-end each customer and automatically the total number is updated.

Best regards.