Night mode is an automatic setting which takes advantage of the new wide-angle camera that's in the iPhone 11 and 11 Pro models. It's equipped with a larger sensor that is able to let in more light, allowing for brighter photos when the light is low.
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Apple Shares New Videos in iPhone Tips Series Covering Wallet, Face ID, Live Photos, Apple Support App and More
The new videos cover getting help on Apple products using the Apple Support app, unlocking the iPhone with Face ID, accessing boarding passes in the Wallet app, and choosing a new key frame in a Live Photo. There's also a video highlighting the fact that Apple's iPhones are water resistant, which pertains to the iPhone 7 and later.
Each video's description links to Apple's full iPhone tips website, which includes additional short tutorial videos and tips on available iPhone features.