...
You will be presented with a list of your CHR machines and licenses:
To upgrade from a Trial to a Paid license click 'Upgrade', choose the desired license level (it can be different than the level of the trial license), and click 'Upgrade key':
If there are prepaid keys available, it is possible to use it for CHR - press "Pay using Prepaid key". If there is no prepaid keys or you do not want to use them, press "Proceed to checkout".
Choose the payment method: It is possible to pay using credit card (CC) or PayPal.
License Update
...