Seems Apple Pay is merely a method of transferring payments from credit/debit cards in Wallet to merchants and websites ... it is not an account as such, as no money is held in Apple Pay.
Wondering if you may have set up Apple Cash for sending and receiving money with people you know and trust.
How to: Set up Apple Cash - Apple Support
How to: Send and receive money with Apple Cash - Apple Support
What to do: If you can't send or receive money with Apple Cash - Apple Support
How to: See your Apple Cash transactions - Apple Support
How to: Transfer money in Apple Cash to your bank account or debit card - Apple Support
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Your Aunt may need to verify her identity to receive money you sent:
See how to verify your identity if required.
Scroll to: "How to verify your identity for Apple Cash" in article below:
Identity verification for Apple Card or Apple Cash - Apple Support
All the best :-)