My MS PC management website, 'remove PC'

Here is my management page for 6 of my pc's.
What would happen if I do the 'remove PC', by clicking top right dots.
How does that affect my logging into my PC on the PC on a reboot?
What does that do?

It does not affect the PC at all. It only removes the association of that PC with your Microsoft Account. If you should happen to log back into that PC with your Microsoft Account, it will show right back up there again.