I'm trying to create a PO for service, I want to enter it as an expense. I checked we have set up the expense category list. But I am not able to see anything when I try to pick the expense category.

that field sources values from

Setup >> Accounting >>Expense Categories.

You dont have to use Expense categories, you can just enter the Account

I can’t see anything under account either

Selected a subsidiary in the header?

I’m using Admin role