In order to make Apps available to be added to your SharePoint 2019 farm, you need to enable Apps in your SharePoint farm. Here are the steps to do so:



Step 1: Go to Central Administration 


Open SharePoint 2019 Central Administration

From your SharePoint Server 2019 farm, open SharePoint 2019 Central Administration



Step 2: Go to Store Settings


Navigate to Apps and Configure Store Settings


Step 3: Make sure the App Purchases are enabled


Make sure you have Yes for Should end users be able to get apps from the SharePoint Store?




Thank you!