you can on my EVGA Z370 FTW .... Under Advanced/Onboard Device Configuration
the slots are disabled by default. I’ve installed new drives and they aren’t recognized until you enable the M.2 slots. As a note, on this mobo each M.2 will use 4 shared PCIe lanes and knock out two SATA ports.....I have two M.2 drives installed and now have only 2 of the 6 onboard ports available. Other mb may not have this same limitation.