My desktop has a Ryzen 5 2400G APU and VRAM is allocated from main memory as set by the UEFI. I wanted to know its proper capacity, so I ran the following command to find out the current VRAM usage.
This is trickier than it first appears because in order to achieve what you are looking for, the Video Graphics card must have vRAM installed on it.
If the card does not, it relies on the motherboard RAM to allocate and use as vRAM.