Appointment comments are used to include specific details to a single appointment, whilst Patient notes permanently display on each appointment for a patient until it is removed or updated.
For example, a Patient note advising 'Hearing impaired' displays on all appointments scheduled for the patient. You may want to book an appointment to review their medications, in which case you could add 'Medication Review' in Appointment comments, as this is appointment specific:
Note - Appointment comments and Patient notes are free text entry sections and are not coded on the patient record.