Can anyone tell me the difference between A1 and A3 commercial property categories?

I need to know what property license I will need to open a coffee bar. I can't seem to get an answer from local councils!
A1, A2, A3, B1, B2 etc is the classification of the use of commercial proprties for planning purposes. Your confusion might be arising from the following:

Class A1. Shops (Retail)
(d) for the sale of sandwiches or other cold food for consumption off the premises,

Class A3. Food and drink
Use for the sale of food or drink for consumption on the premises or of hot food for consumption off the premises.

Since you are opening up a coffee bar, you will be preparing and serving drinks on your premises so you would definitely need to apply for consent of A3 application.

Hope this assists you and good luck with the new venture.
A1 is a shop. A3 is restaurant or cafe
a3 is fast food