it should tell you in the motherboard manual
an example out of an MSI manual (its an old manual, headings may have changed)
What enabling this does is swaps Boot method to UEFI only, and enables the Secure Boot Menu
Secure Boot is up to you, it stops windows booting from anything other than the drive its installed on, although there are ways within windows to boot off a USB or other drive if needed.
I would enable Whql mode
Other OS is defined as any version of WIndows prior to Win 8 or another OS that still uses Legacy boot method
Legacy boot only supports MBR drives and is the format used by almost all OS prior to 2009
UEFI (Unified Extensible Firmware Interface) supports both MBR & GPT drive format and was designed to fix many of the limitations of Legacy boot. Almost all Motherboards since 2009 are UEFI bios.
MBR = Master Boot Record. Drive format used on all Windows boot drives prior to 2009. ONly allows 4 partitions max (although there are work arounds) and max partition and/or hdd size is 2.2tb
GPT = Guid (Guid = Global Unique ID) Partition Table. Format created to fix MBR limitations. Can have up to 256 partitions on a drive and max drive size is 18.8 million tb
Win 10 supports UEFI and GPT by default, and will insist on using them if it recognises motherboard supports both.