Can I boot memtest86+ if I'm using UEFI?

Memtest86+ does not work in UEFI mode

Memtest86+ does not work in UEFI mode because it is a 16-bit program. But if you can boot the computer in BIOS (CSM, legacy) mode, it works.

See this link

Where is the memtest option on the Ubuntu 64-bit live CD?

Memtest86 works in UEFI mode

There is another version, the 'original' but now not FOSS version memtest86, and it works in UEFI mode. There is a commercial version and a free version (no cost, but not open source code).

See this link

www.memtest86.com/download.htm

Adding newest freeware memtest86 to UEFI Grub2

Here is a great tutorial on how to add the freeware memtest86 to UEFI Grub2. It's especially useful if you are working on a remote machine, and inserting a physical usb is out of the question.

See this link for the Ubuntu oriented tutorial.

https://www.yosoygames.com.ar/wp/2020/03/installing-memtest86-on-uefi-grub2-ubuntu/

See this link of an example of doing this on a remote server, but based on the above tutorial.

https://unix.stackexchange.com/a/632700/253599

Is there a way to add it to the install options?

No.

Best alternative: create a live boot memtest usb/dvd. You can create it from Linux, Mac or Windows (basically they provide an installer for all three but the software itself is identical).

For UEFI you need the MemTest86 v7 Free Edition version (link below downloads that one). Instructions for the USB version (there is also a DVD version and a floppy disk version at the links above):

Create a bootable USB Flash drive:

• Download the Linux/Mac MemTest86 USB image.
• UN-tar the package (tar xvzf MemTest86-*-usb.tar.gz). An image file and a
• README file will be created in the current directory. Follow instructions in the README to write the USB flash disk.

Pretty generic.