I recommend buying 2 memory modules to fill 2 memory banks. This way you can use the Dual Channel Memory Architecture and have a speed advantage.
The following memory is 100% compatible:
HyperX Fury (2x, 4GB, DDR4-2133, DIMM 288)
HyperX Predator (2x, 4GB, DDR4-3000, DIMM 288)
G.Skill Ripjaws V (2x, 4GB, DDR4-3200, DIMM 288)
Do you want a total of 8GB? If you also want to do games or video editing on the computer, I recommend 16GB. For internet or work, 8GB is enough.