What RAM is compatible with AMD Ryzen 7 4800h with Radeon graphics? can I use ddr5 ram with it?
DDR5 isn't compatible with 4000 series processors so you can't use DDR5 RAM for your laptop. You must install DDR4 RAM.
You need to go to your Laptop Support and find out which RAM is compatible with your Laptop.
Or google your Laptop Make & Model for RAM Upgrade and see which vendors sells compatible RAM for your laptop.
NOTE: your Post is very vague so it is impossible to give you any specific answers to your question.