How to close MacBook and Use Monitor (Clamshell Mode)

• Make sure the external keyboard, mouse, power adapter, and external monitor are connected to your MacBook ,MacBook Air, or MacBook Pro.
• Put the machine to sleep and close the lid
• Keep the lid closed, press any key on the external keyboard to wake your MacBook/Pro from sleep

So the mode:

Clamshell mode (Lid Closed)

for MacBooks [Intel or Arm] is entered automatically, if you have connected:

[1]-keyboard, [2]-mouse, [3]-display... and [4]-power...

And also, there is NOT any specific setting for this...

All correct?

My caveat about clamshell mode is heat. Some Macbook Pros draw cooling air in through the keyboard. In this article:

Keep your Mac notebook within acceptable operating temperatures - Apple Support

Apple says, "Don’t put anything over the keyboard." 

To me, closing the display puts something over the keyboard!

If your Macbook Pro has side vents, this is less of a problem. However, not all Macbook Pros have side vents.

Another common mistake that people make when using clamshell mode is to put the closed computer vertically like a book on the workstation to get it out of the way.

Therein lies the problem. If you place it vertically with the hinge down, YOU BLOCK THE CRITICAL EXHAUST VENTING! High heat can cause premature failures.

If you must do this, place the computer with its hinge UP.

The other item worth mentioning is that the article that USED TO tell you exactly how to do this has been removed from the knowledge base.

That makes it appear Apple is not interested in supporting this use in the long run -- so don't get hooked on it, it could be deprecated in the future.

Correct