Help... shower mixer taps..

Hello.. Newbie to all this so havent really got a clue.. but I have broken taps in the shower in my caravan and looking to replace them but not sure what they are called or what replacement to get.. any and all advice welcome, not really sure where to start! The problem with them was one of the taps was stiff and when turned snapped off so the water shoots out the tap now instead of the shower head! 🙄😂

Thanks in advance :)