Tickets for the GVB trams, buses and metros can be bought in the GVB app.
The app allows you to purchase GVB tickets for 1, 24, 48, 72, 96 and 120 hours. You activate these tickets in the app by using the QR code and you are ready to travel. Simple check-in and check-out, also for multiple people on 1 phone. No WIFI required at check-in.
Also in the tram or bus it is possible to buy a ticket at the conductor (with card, no cash).
NS train tickets can be bought in the vending machine at the station.