The motherboard, also called the logic board or mainboard, is a board with electrical circuits printed on it that holds many of the computer's essential components. The electrical circuits on the board allow the components to receive power and communicate with each other.
A desktop computer motherboard usually contains the CPU and the main memory, and you can attach graphics and sound cards, memory, and other peripherals to them with cards or cables. It's also very common for manufacturers to integrate some of these components directly onto the motherboard itself.
Integrated boards are usually less expensive and easier to manage since they come in a nice, tidy package. But they don’t offer the best performance, you can’t upgrade the components, and if something breaks on an integrated board, you have to replace the whole board.