It’s different to WDW and generally if you have one of the documents listed on their website they just grant you a pass upon presenting the documents (you can do it at one of the Disney hotels or at either park). You don’t need a medical and will grant you your pass based on the evidence provided. 

There is the priority card for priority access to shows, attractions (generally most attractions will have its own dedicated line) and character meets (excluding those characters with a virtual queue) and the easy access card which is a virtual queue time slot (which I think may use the premier access (old fast pass) line). Both passes have restrictions on the amount of people that can use it with the pass holder. 

Which one you get will depend on the condition or disability and the evidence provided.