If you’re talking about a Monzo.me link (where they enter their debit card to pay you), then it might work. It depends on the country the debit card is from. This is the list (I know it refers to “top-ups” which don’t exist anymore, but the same country list is used for Monzo.me), press the to make it more legible:
In terms of what they will be charged, it depends what (if anything) their bank charges them for using their debit card in the UK.
to make it more legible: