One of the more useful actions that 3D Touch makes possible is pressing an iPhone's onscreen keyboard to turn it into a virtual trackpad. If you 3D Touch, the keyboard turns blank and morphs into a trackpad that allows you to quickly move the cursor on the screen through the text you've written.
This popular gesture is useful because it allows you to make quick edits without having to reach up and tap the display. However, in its latest crop of devices, Apple has replaced 3D Touch with Haptic Touch, and the way the virtual trackpad activates has changed slightly.
It's a small adjustment, but it's worth highlighting in case you tried to activate the virtual trackpad on your new iPhone in the traditional way and wondered why it wasn't working. Note that the gesture functions similarly on all Apple devices that lack 3D Touch, including the iPhone XR and all models of iPad.