Problems installing Linux Ubuntu through USB

I used to install Linux Ubuntu 18.04 to a 32GB memory stick, and I managed to boot it everywhere. But now I’ve problems due to uefi and secure boot. I want to provide a distro from a usb key with a lot of programs for a classroom, and all students are working on their pc while using Linux distro without an installation. I want to mention that I don’t have a uefi-secureboot machine to try. Any ideas about how it might work are welcomed.

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