American English speakers say apartment, and British English speakers say flat.
A studio is a specific type of apartment or flat – it is just one room, with no walls or
divisions between the bed area, the kitchen area, and the area with a couch or TV.
The word studio is also used for:
▶️ a place where singers/bands record and produce their music
▶️ a place where movies, TV shows, or radio programs are produced
▶️ an artist’s or photographer’s working space