When you press and hold your finger down on your iPhone and feel a tiny vibration, that's haptic feedback.
Apple's version of this technology is called Haptic Touch, and it allows you to do a number of things across the iOS ecosystem by long-pressing your finger on your display. It mostly brings up menus filled with actions, like delete, share or view more, but it's also how you get your apps into "jiggle mode" and turn live photos into videos.
I use it all the time to quickly change the intensity of my phone's flashlight and use my keyboard as a touch pad.
It's a useful feature to quickly and efficiently navigate iOS, akin to keyboard shortcuts on your computer, but if you feel like Haptic Touch is a little too slow for you, you're not the only one.
There are people out there, including me, who feel that Haptic Touch is too slow to react. Apple's previous haptic technology for the iPhone was 3D Touch, and it worked by pressure sensitivity, not length of time, and so it was punchier than Haptic Touch.
Apple replaced 3D Touch with Haptic Touch in 2018 with the release of the iPhone XR.
Now, we're stuck with Haptic Touch, for better or worse, but there is an easier way to make Haptic Touch faster, so that it more closely resembles 3D Touch. Here's where you can find the setting to make the change.