You can go to the "hard" console using the keys Ctrl + Alt + F1 , F2 , F3 ; In it you will have to re-enter the username and password of the user. This console is useful for cases when the graphical shell is somehow broken and needs, for example, a reboot.
You can go back using Ctrl + Alt + F7 (sometimes F8 )
If you need a server completely without a graphical shell (this is useful for saving resources, for example), then you can immediately install the system accordingly. Or reconfigure existing:
(thanks to alexander barakin for the addition)
I confirm LEQADA's doubts: in Windows there is no possibility to install the system without a graphical shell at all, but you can boot into safe mode only with the command line. Removing explorer.exe will not lead to anything good.