To add more credits to your account without the need of creating a new user or additional e-mail, please follow these instructions:
Go to your dashboard and click on your avatar icon located on the upper left corner > Billing:
In the section "Your plan details", click on: "Get More"
The two next steps must be filled but keep in mind that they will NOT add a new user, just the credits for the new license.
Select the role for the license (we recommend member):
Finally, include a new e-mail in order to finish the process. Below, you will see the price for the new license.
Once you've finished these steps, you will already have the new credits in your account. Don't worry, the e-mail you've added will not receive an invitation.