I just changed the water pump now there's water in my oil not just on the cap?

Hello,

When you change the water pump there is no opening for oil and coolant. There is no passage for the coolant to go into oil.
Only way coolant can get in oil if there is a leak, like a blown head gasket.
Did you have overheating issue before the water pump replacement?
If an engine overheats it can blow the head gasket due to increased pressure. When that happens the oil and coolant will mix. You will typically gat white smoke out of the tail pipe.

https://www.2carpros.com/articles/white-smoke-or-steam-coming-from-the-exhaust-pipe

First thing you need to do is to do an oil change, before you even start the engine. Then flush the cooling system.
After that check for a blow head gasket. There is a tester you can use to check for combustion gases in your coolant. Which is sign of a blown head gasket.

Here is a helpful video:

https://youtu.be/5zpNjYmmiYY

https://www.2carpros.com/articles/head-gasket-blown-test

If your coolant is contaminated with

I have attached diagrams for your reference.

Please let me know of any questions.

Thank you.