The usual way is to go into BIOS and to disable it there.
If you are not sure how to enter your BIOS (it depends on manufacturer) you could try to boot into BIOS settings with this command:
systemctl reboot --firmware setup
Positional argument to reboot command is deprecated, please use --reboot-argument= instead. Accepting anyway.
Failed to write reboot parameter file: Permission denied
.
Hm, I'm not sure. You could try this
sudo systemctl reboot --firmware setup
Nevermind, I don't see secure boot at all... but only thing that I see is secure boot mode and there's only 2 options: enabled, and custom.
Please take a look at the manufacturers site how to disable secure boot or tell us the brand/model of your computer or motherboard.
Perhaps there is another option to enable or disable secure boot, at another place than at secure boot mode.
You can also take a screenshot of the BIOS secure boot settings and post it here.
You could try custom and see if You get with this additional Options. But it depends of the Manufacturer.
So, You are not really sure what Graphics do You have? Type in the Terminal sudo lshw -C display and post the Output here.
*-display
description: VGA compatible controller
product: NVIDIA Corporation
vendor: NVIDIA Corporation
physical id: 0
bus info: pci@0000:01:00.0
version: a1
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress vga_controller bus_master cap_list rom fb
@worthless I see that the system doesn't know what your GPU is, only that its an Nvidia GPU. I hope you have Secure Boot disabled in the BIOS.
According to the Nvidia community, an Nvidia RTX 4090 GPU, should be running the 566 driver bare minimum, and is recommended by Gamers Nexus as well. Make sure you have that set in Additional Drivers.
So I should go with Using NVIDIA driver metapackage 566 for my RTX 4090 correct?
I do not see 566 driver, what NVIDIA driver should I go with for my RTX 4090?
What does custom offer?
I believe that was a typo, and @StarTreker meant 565 driver minimum. You can select the 575 or 580, too.
I can’t upload bruh
Try to set at "OS Type" > Other OS and look if then secure boot is automatically disabled.
Same thing
And at "secure boot state"? What is shown there when you select other OS?
You don't need to post twice, I see your posts.
User that what it say
On the previous page in your BIOS, can you show the settings there, please (go back with 
button)?
