USDM to fiat wallet

Hello, I had BTC, sold some of it for USDM (because I thought I could sell it for fiat), but I would want to convert the USDM into my fiat wallet and later when I receive your Visa card, I want to pay with it. Or what do I have to do to pay with your card when I own some crypto. (BTW I'm still waiting for the card, I don't have it yet) Thanks