The type of apartment you are referring to is commonly known as a "studio apartment" or "efficiency apartment." Studio apartments are typically small, self-contained living spaces that consist of a single open room, which serves as the living area, bedroom, and kitchen combined. They usually include a bed, a desk, a closet, and a simple kitchenette or kitchen area.
The main characteristic of a studio apartment is its lack of separate rooms for different functions, making it an ideal choice for individuals or couples who prefer a compact and minimalistic living space. Despite their limited square footage, studio apartments are popular in urban areas due to their affordability and convenience. They provide a simple and efficient living arrangement for those who don't require a lot of space or want to live in prime locations with easy access to amenities and city life.