Admins can receive text (SMS) notifications about appointment and form submissions. To set this up:
Add a custom field for Phone Number to admin users. Set this up under Settings > Fields and add Phone Number as a field to Bookable People/Things
Set phone numbers for your admin users in Availability > click on a Person > click "Edit" > enter a phone number then Save
In Forms > edit a form > Automations add a new automation to send a text message when an appointment is booked or upcoming then set it to send to the Bookable Person/Thing