It is possible to install Windows on some Chromebooks such as the HP Chromebook 11 G4, the procedure isn't the same as with standard laptops that have been designed directly for Windows.
As there are places on the web that go into the technical side of the installation and firmware requirements, we will only briefly go over links to other tutorials and modified drivers by coolstar.org will be also below.
Custom Firmware:
Ultrabook to Chromebook Reddit community:
https://www.reddit.com/r/chrultrabook/
In particular read:
https://www.reddit.com/r/chrultrabook/comments/aufp1q/getting_started_read_this_first
Interactive setup and driver download:
https://coolstar.org/chromebook/windows-install.html
Good luck, this will void any warranties, will purge all data on the device and has a good chance at bricking the device. Proceed with caution.