Do I need a reservation to enter to the store in Miami?

Depending on the specific store you may or may not need an appointment. Apple is currently limiting stores to service and express pickup in most locations.

See here: Shop with a Specialist - Apple

Your best bet is to purchase on line with pick up from the store of your choice in the Miami area. This way you do not have to worry about getting an appointment to shop which are not granted in most states at the moment. Just make sure that the item that you purchase is available at the store where you want to be. Express pickup appointments can be made right after the purchase(s) is complete.

Axel F.