If you mean the IP address on your internal network (LAN) you can create a static address on both the computer and in the router. You have to have access to the router to do this, otherwise ask the person who controls the router.
It depends on your router, some allow address reservation and all of them allow you to enter a static address for a specific computer (or other device). You will need the MAC address of the computer to enter it in the static table of the router.
I can give you more detail if you tell me your router brand and model.