Stands for “Unified Extensible Firmware Interface.” is a new type of computer firmware that has many advantages over the traditional BIOS. First, it has a user-friendly graphical user interface that supports rich colors and animations.
It supports the new GPT partition scheme that supports larger storages, unlike the MBR that limits at 2TB. On top of that, it also allows you to use a mouse, keyboard, and even touch as input for configuring the settings.
More importantly, it has a built-in feature called secure boot that protects your computer from loading uncertified bootloaders, operating systems, and malicious software.
You can learn more about Surface UEFI from the following resources: