Learn how to use app extensions on iPhone 6. Some apps let you extend the functionality of your apps on iPhone. An app extension may appear as a sharing option, action option, a widget in Notification Center, a file provider, or a custom keyboard. For example, if you download Pinterest to iPhone, Pinterest becomes another option for sharing.
App extensions can also help you edit a photo or video in your Photos app. For example, you can download a photo-related app that lets you apply filters to photos from your Photos app.
For more information about Notification Center widgets, see Notification Center