I don£™t have a I gpu option on my bios

The information you are giving is not enough for a proper answer.
But here are some basics.
manufacturers stopped using graphics chips on the board itself, years ago
Both Intel and AMD have integrated their graphics into the CPU, so what is still called onboard, is actually integrated in the CPU.
Intel has released a series of CPU's where the type ends on F which do not have integrated graphics, so the onboard graphics ports, cannot work
https://ark.intel.com/content/www/us/en/ark/compare.html?productIds=134590,134589
AMD Ryzen, works the opposite way, they don't have integrated graphics, but processors with integrated graphics, (also called APU's) have a type name ending on G or GE, you can see this also mentioned in the CPU support list from the particular AMD board,
https://www.amd.com/en/products/specifications/compare/processors/8451,8476
So Integrated GPU, is only available with certain CPU's.
When You use a CPU with integrated graphics, part of the RAM memory, is dedicated to the CPU graphics unit.
When inserting a discrete graphics card, the "onboard" IGPU will always be disabled, to free up RAM memory.
In most cases the BIOS has a Share memory Size option, when set to auto this rule applies.
When setting it to a predefined size, the onboard graphics should stay active