… can I install normal ddr4 (used on pc motherboards) on this motherboard?
From the information you provided it look like you can. However, in doubt contact Dell, or ask the memory vendor. Most vendors offer a selector from which you can select your system, which will then show supported memory. Also keep in mind that ECC, and non-ECC memory usually cannot be mixed, and that it may be necessary to add memory in pairs. So make sure that you gather the required information before you purchase additional RAM.
Hint: Once you have the system, use e.g. CPU-Z to find out the specs of what RAM came with the system.