OVMF (Open Virtual Machine Firmware)
OVMF is an UEFI implementation to be used on QEMU. It is free and open source software. It is part of Tianocore's EDK II project. Tianocore is a community open for developers and having of stewards (guides) from Apple, Intel, Nuvia and Red Hat.
Many Linux distributions let you install OVMF with their default installer.
For example on Debian/Ubuntu and derivates:
sudo apt install ovmf
Or on Arch/Manjaro and derivates:
sudo pacman -S ovmf
You can also get ready-built OVMF files from this repository:
Many useful informations including an FAQ are here: