Most of the time, you’ll want to use your laptop with it open. This gives you full access to the keyboard and trackpad as input devices, as well as the attached display, which may or may not have a touchscreen.
How to Connect Your MacBook to a Closed Monitor (Clamshell Mode) in 2021 – EASY
However, when you’re at home or in the office, you may want to connect your laptop to a separate monitor, keyboard, and mouse. This can mean more screen space to work with and a larger keyboard to type on. Plus, it can improve your posture at your desk.
However, to use your laptop in this way with the lid closed, you need to adjust a few settings. Otherwise, your laptop will assume that you no longer need it and will go into sleep mode when you close the lid.
First, connect all your peripherals to your laptop. On both Windows and macOS, devices such as keyboards, mice, and monitors are immediately detected and automatically sent to work. So you can close the lid of your laptop when you're done.
