It's easy to upgrade your ServerPilot trial period account to a paid account.
First, open the Billing tab of your Account page in ServerPilot.
Next, click Update Credit Card.
Enter your credit card information in the popup and click Add card.
Once you've added your card, your trial will automatically end. If you had a trial server on your account, that account will automatically be switched to the Economy plan and you'll now be able to enable AutoSSL, create multiple apps, and manage each app's domains.
To change your server's plan, click on the server in the servers list, then click on Plan, then change the server's plan.