Can I pay for my ticket on the Copenhagen Metro with a credit card directly ?

Of course, in Northern Europe, almost all consumption can be paid by card, only going to the toilet is not allowed.

The itinerary is the same as mine at the time, and credit cards can be used. However, I think I took the train to the airport. It's only three stops from Copenhagen Central Station to the airport.

I recommend that you buy a 24-hour or 48-hour pass at the airport after getting off the plane. You can take the subway, bus, train, and S train as you like, which saves money. If you want to go to Elsinore to see Hamlet's castle, you need to buy a pass for the entire region, which is more expensive, 160 DKK per day. If you just want to walk around central Copenhagen, you can buy a ticket for zones 1 to 4, which is 80 DKK per day and cheaper than buying individual tickets. You can also consider the Copenhagen Card, which includes tickets for most attractions and is even more cost-effective.

It's best to exchange some at home.