apple pay

Generally yes.

(If ApplePay is accepted by the particular POS terminal … but like in the U.S., acceptance is not “universal.”)

You might also wish to confirm w/ your individual Credit Card issuers as well.

(the ApplePay technical “piece” might work but if your issuer still “rejects” the transaction …

See:

Countries and regions that support Apple Pay - Apple Support

It’s always safe notify the issuers of any cards she intends to possibly use overseas. (Although this is NOT necessary for an AppleCard Mastercard)

And DO have her “test it” soon after arrival.

(i.e. buy something inexpensive while still having sufficient Euros in her pocket to “cover the transaction” if there IS problem)

For AppleCash, Green Dot Bank’s contact info is provided in the “Terms & Conditions” within Wallet.

If she is using a credit card, be sure to use one that doesn't charge international fees.