ERPNext Healthcare allows you to create multiple physicians and optionally link to a User with appropriate Roles. You can create a Physician here -
Healthcare > Masters > Physician
Linking a User to the Physician makes the system populate the Physician field in all documents to the Physician associated with the logged in User.
Note: You should also relate the User to an Employee to utilize the various features of Human Resources module.
Scheduling and Availability
Each Physician can have a "Physician Schedule" and a "Time per Appointment" on the basis of which, the scheduler will book Appointments. Also, you can select appropriate Income Accounts for a Physician to book all Consultation charges into separate accounts.
You may also want to manage a list of Doctors who refers Patients to your facility. You can manage such data in the Physician document itself by leaving out the User link.
Next: Physician Schedule