Hi @JimK
UEFI (sometimes referred to as EFI) is now the standard technology used to boot a computer, although both UEFI and the previous MBR boot (Legacy) system are still possible. However, these two technologies are mutually exclusive.
When multibooting, for example, you can’t use both of these technologies at the same time. Though, this isn’t strictly true, as there is a subset of a UEFI base motherboards called the Compatibility Support Module (CSM), which emulates a traditional BIOS boot; which does arguably allow both.
However, for the sake of simplicity, it’s best to use either one or the other; especially in a multiboot environment where having CSM enabled can be detrimental to an EFI-booting OS successfully launching. To ensure only UEFI booting is used (on a UEFI-capable machine), one must usually change a few settings in the BIOS.
The boot scenario you have should also inform the tools and procedures used during installation and maintenance. The distinction between UEFI and Legacy booting is important, and I suggest you learn as much as you can about the differences between them, before progessing much further.
- What Is UEFI, and How Is It Different from BIOS?
- UEFI (Wikipedia).
- UEFI Install Guide (Manjaro).
- Dual boot Manjaro and Windows.
- Unified Extensible Firmware Interface (ArchLinux).
- Your favourite Search Engine…