If you are going to send more amount as per set limit or make a Cash app refund more then sets a limit, then you need to provide your SSN here to verify you and your account. SSN is a social security number that asks to confirm for federal anti-money laundering and anti-tax evasion regulation. If still any queries, then reach us. https://www.techjaadu.com/blog/cash-app-refund-frequently-asked-questions/