Some public apps are highlighted with the Built for Shopify tag in the Shopify App Store. This tag identifies apps that have surpassed a strict set of quality, safety, and performance standards. You can also find public apps that are made by Shopify. These apps are usually free and supported by Shopify.
Unlisted public apps aren't displayed in the Shopify App Store search results or categories. You can install an unlisted app from the app's App Store listing or directly from the developer's website.
Custom apps can be used to add features to your Shopify admin or to extend your online store to other platforms using custom storefronts. Custom apps are built exclusively for your Shopify store and aren't listed on the Shopify App Store.
An external app developer can make a custom app for you without needing API access to your store and access to your Shopify admin. You can install a custom app by clicking an install link provided to you by the app's developer.
Draft apps are used by Shopify Partners during development and can be installed only on development stores for testing purposes. Installing a draft app on a development store deactivates store transfer permanently.
Draft apps can be installed on your store only after the Shopify review or after a draft app is converted to a custom app.