You can upgrade to any plan through the subscription page before the end of your free trial. You won’t get billed until after your trial period is completely over. Upgrade now, start paying at the end of your free trial!
You will find the subscription page on the web portal under the Subscription menu (bottom left side, 'credit card' icon).
You can select one of the license plans, choose a monthly or yearly subscription (save up to 25% ! ) and select the number of licenses you need.