When you created your Annual Subscription, you were able to select the number of seats you need for your team.
If you need to add more seats to your team:
Go to My Account (you can find My Account by clicking on your avatar in the top menu)
Click on My Teams
Open the Billing Tab
Click Change Subscription
A new window will open. Click the menu and select the new plan.
5. Enter the number of seats
6. Click Confirm Subscription Change
Note: Annual Subscriptions are non-refundable and will be renewed automatically unless they are cancelled before renewal date.
Also See: