can i add any ram to my motherboard

[donnaimon]

so i am trying to add more ram to my tower, at the moment i have 8gb with these as my rams:
sk hynix 4gb 1rx8 pc4-2133p ua1 10 hma451u6afr8n tf no ac.
sorry if its a hassle to understand its my first time upgrading, im not quite sure if i can add any ram that i want, can you please send me in the right direction it would be much apreciated.

 

[donnaimon]

MERGED QUESTION
Question from donnaimon : "any ram for any motherboard?"

i have a IPSKL-SC. HP motherboard from an alien aurora r5, can anyone tell me if its better to buy new rams of to add 2 more since i have 4 slots, thanks