The Pro version costs a couple of dollars. At first, canva charges about $12 per month for a start, then as time goes on, it drops to $9 per month. Canva does not offer a chargeback service, i.e., payment will not be refunded. This payment could be made via google play store for android and ios.
Peradventure you are using a pc, then you will have to make payment using a third party, whether Quickteller or its contemporaries depending on your location. It should be noted that Payment on the platform is 100% safe and secured. Reviews over time had shown that the user tends to enjoy the features of the pro version better compared to the trial version. As such, it is advisable to make a one-time payment, get the best out of it; and if you are 100% satisfied with the service, you can keep the subscription going.