Most headphones have a mini jack, however some come with a full sized jack for use with things that do not have a mini jack socket available.

I bet you're wondering how they work!

Headphones and earphones work in Black Airpods pro the same way as speakers do, but the parts are much smaller (because who could walk around with a full sized speaker strapped to each ear!?) Speakers work by getting the air in a room moving around to allow the sound to travel more freely, which is why if you've ever put your hand on a speaker playing really loud music, it will have been vibrating very hard to ensure the sound is projected. Headphones and earphones use the same idea, except they only have to get the air inside your ear moving, so they don't need to be any where near as powerful.