Turn off external monitor by closing MacBook

When my MacBook is connected to an external monitor and I close the lid it does not turn off the display. From my own research I can only find articles on how to keep it awake with the lid closed but, I can't find anything on how to stop it from sending a signal when closed.

When I shut then open my mac it closes everything on my second desktop and makes my external monitor the main display. I also wish I didn't have to open my Mac and press the button on my monitor when I sit back down. I don't use an external keyboard or mouse so I have no need to use only my monitor.

Can anyone help or give any thoughts?

Thank you