If you published your Blocks App in the Wix App Market and adapted it to a pricing plan, there are a few ways to allow site builders to upgrade their app to another plan. All these ways lead site builders to your app's pricing page.
Blocks automatically adds an upgrade icon to the widget's action bar, once you set up a pricing plan for it. Note that this button cannot be removed.
To see how this button works, test you app in the editor. You'll be able to see it on a live site once the app is published in the App Market.
Add text and a link from a custom panel, to enable site builders to upgrade the app from a panel.
To add a text and link to your panel:
Add a link or a button to your Dashboard page, to enable site builders to upgrade from their Dashboard.
To add an upgrade button or link to your Dashboard:
For example, if it's button: