Hi @thony_cruz_aguay , welcome to Open Zeppelin.
If the contract can receive them then they go to the Contract and are held there.
If they cannot receive them then the transaction will fail.
You can also build contract functionality that handles receiving tokens and do specialized functions.
As you are new I highly recommend getting started with this tutorial
You don't have to understand it 100%, but it's a great way to get you up to speed and get a developer environment going.
After that check out
I know it's a pain to go through all this, but as you learn you will give yourself the skills needed to create any type of smart contract you want.