I played Sims 4 on the computer and downloaded the cd on the computer so I paid money for it. Is there a way that I don't have to pay Sims 4 again for the ps4?
No.
No! If you want to play it on PS4, you have to buy it on PS4 too!
I just found the following article:
https://www.spieletipps.de/n_36545/
With a little effort, this is actually possible, provided the game is a steam game.