The User Manual should explain what each of those do and are used for.
For the sake of an answer that is not go off a read the manual, it depends on what you are trying to accomplish.
If I read into what you are saying, you want to know how to reset your PL logic when the board is reset?
If this is true, the PS_POR is the processing system power on reset. Whenever the power supplies are reset, that will also reset. You can use that to reset your logic.
There is also the PS_SRST, typically that is a system reset that is controlled by the PS. In some of our designs, you will see that or the POR is tied to an external button.
I suggest you determine the reason and the action that could cause your logic to need to be reset, and then investigate which one of those you want to tie to.