Ultra sound picture question!

Racheal • First Time Mommaa | 17 &&&' Pregnant | Due Sept 15th | Blessed With Our BabyGirl Leiana Ann Pritchett💖👶🏽👨‍👩‍👧😍🎀
I may just be having a moment right now but I'm a little confused . What's the difference between 3D and 4D ultrasounds ? I've heard of both I just not sure ..Which one would you recommend getting? Or does it not matter ? I'd really want a clear visual of my baby girl next ultra sound I get .