Each appointment type, when you create it, has the option to send a reminder(s) at a chosen time interval before the appointment. This option appears in the “Reminders” tab of the Appointment Type wizard (the specific appointment type in edit mode). If you do not want to send the reminder, you can remove the reminder by choosing 'remove' from the drop-down gear box to the right of the Reminder and clicking save.
As a reminder, this will affect everyone who has an appointment of this type scheduled, meaning that anyone who has scheduled this type of appointment on your calendar will no longer receive the reminder. If you have only 1 client that you want to remove reminders from, then it would be easier to create a specific appointment type for that client and remove the reminder from that. This way, no one else is impacted. Or, if you schedule the appointments for that particular client, you can leave the reminder option unchecked in the scheduling pop-up window.
This is the case for individual appointments that you set, but there is no option to send (or not send) the reminders when the client schedules the appointment themselves. Is there any way to turn off the appointment reminders when the client schedules the appointment?
There is no difference in this regard between appointments scheduled personally by the coach and the ones scheduled by clients/prospects. The coach can go to any appointment in the calendar or under the Appointments section of the client/prospect (CONTACTS TAB > CONTACT NAME > Appointments tab) in edit mode and turn off the reminder option by unchecking it and saving the change.