Not sure by what you mean if the integrated Graphics of your APU is compatible with a Nvidia or AMD GPU card.
As long as your Motherboard has the correct PCIe x16 slot and PSU GPU Power connector , if applicable, it should work. Depending on the processor it might affect the performance of your GPU Card.
when you install the GPU card, your motherboard's BIOS, if configured to "Auto", should automatically make your GPU Card the main Graphics to start when you boot up. If you have in BIOS configured to use your Integrated Graphics than it will ignore your GPU card until you change it.