Once you purchased Viral Dashboard, you will see options to upgrade to various plans because there are several plans in Viral Dashboard depending upon features and addons.

Once you purchased a plan or upgrade to another plan, you need to sync the plan in order to activate that plan. For this, you have to go to the Billing Section and click on the Sync Plans button. See the image below for reference.

Also, to upgrade plans, you can contact the support team via email.