Apple 3D Touch is a hardware-based feature Apple introduced in iPhone 6s and 6s Plus devices running iOS 9 that perceives the amount of force a user puts on the touch screen to activate different functions.
With Apple 3D Touch, users can take actions without navigating away from the original screen they were on. Swiping or pushing on the screen with more pressure allows users to preview email or other content, access specific application functions from the home screen and more. Pressing on the left side of the screen, for instance, enables multitasking view, which allows users to swipe between open apps to find the one they need.
Peek and Pop are two of the main features of Apple 3D Touch. With Peek, users swipe up from the bottom of their screen, and a menu appears with a set of app-specific functions. In the Safari browser app, for example, the menu provides options such as opening a new website tab or copying the URL. The Pop function brings up a full-screen preview of content within an app, which users can access by applying more pressure to the screen.
Quick actions with 3D Touch allow users to access specific app functions from the home screen instead of actually launching the app. Pressing deeply on an app’s icon on the home screen opens a small window with a title, icon, and -- if the developer includes it -- a description of what the quick action does. Developers can set up quick actions to bypass certain aspects of the app, so users can access the functions they use the most. For example, quick actions on a GPS app can bring up directions to the user's home. In addition, the content that quick actions provide changes depending on the user's location or what they are using their phone to do.
With Apple 3D Touch, a tap of the keyboard in writing-intensive apps such as Notes turns the keyboard into a touch pad. Pressure-sensitive drawing with 3D Touch gives users the power to create lines with different thicknesses depending on how hard they push on the screen.