To uninstall an app from your Shopify admin, follow these steps:
Navigate to Settings and then click on Apps and sales channels.
Find the app you want to uninstall and click the three dots (…) next to it.
Select Uninstall. You can also select a reason for uninstalling the app from the Reason for uninstalling (optional) drop-down menu and click Uninstall to complete the process.
Here is a quick video with instructions.
View apps that have been uninstalled from your store
You can view both installed and uninstalled apps from your store from the Apps and sales channels page in Shopify.
Steps:
From your Shopify admin, go to Settings > Apps and sales channels.
Select the Uninstalled tab to view your uninstalled apps.
Uninstalling an app will also mean that your subscription for that app has been canceled. Therefore, you will not be billed for the app's usage in future months.