Cash app cards also work as a traditional debit card which mainly work as a reloadable prepaid card. It is used for payment when you are shopping. You can simply add money at Walgreens from it. If you don't have an idea how to add money at Walgreens from the Cash app then you can ask the shopkeeper or simply go to add money option to add. For more information, you can talk to Cash App Customer Service to resolve your all queries.