Thank you for writing to confirm our appointment regarding [topic]. I have you scheduled on the calendar on [date] at [time] at [location]. Please contact me at [phone number] or [email address] if you have any questions before the meeting. I appreciate your timely attendance at this appointment.
Moreover, how do you reply to please confirm?
a reply email with a response of acknowledged/ confirmed/ received and a word of thanks (if what you received was beneficial. A longer, complete-sentence response (with thanks if needed) is more polite and should be used if dealing with a customer or a reader who would expect respect.