If you want to add money to the Apple Pay to Cash App then follow the below steps:
Open the cash app on your mobile
Click on the Money card and choose the picture of your money card
Select on the Add to Apple pay option
Follow all the instructions and confirm your debit card which going to be added to Apple pay
Click on the Done button once the process will complete
https://www.experts-support.com/blog/transfer-money-from-apple-pay-to-cash-app