By default, apps don't do anything. They're just containers with some metadata (title, description, etc).
For an app to do something, it must have one or more extensions. An extension is what adds functionality to Canva, such as a destination in the Publish menu or image filters in the Effects panel. You can think of extensions as features or capabilities of your app.
You can add the following types of extensions to an app:
Refer to the linked pages for more information about each type of extension.
Apps can have more than one extension.
If an app supports multiple extensions:
Users don't have to connect multiple apps. Connecting an app doesn't take a lot of effort — it's literally the click of a button — but providing more functionality with less effort is a more delightful experience.
Users don't have to authenticate with multiple apps. If an app supports authentication, the user only has to authenticate once for the entire app. If features are spread across multiple apps, they have to authenticate separately for each app, as authentication is not shared between apps.
Apps can't have more than one extension of the same type. For example, it's common for apps to have a content and a publish extension (one for importing content, the other for exporting it), but an app can't have two content extensions.