Burst mode on iPhone is a great way to ensure you capture the photo you truly want, especially when your subject is moving too fast. You'd be forgiven for thinking that Apple ditched the feature entirely on iPhone 11, 11 Pro, and 11 Pro Max, since a long-press of the shutter button now records video instead. However, burst mode is alive and well on your new iPhone — it's just hidden.
See, the 2019 iPhones don't implement burst mode the same as the rest of the iPhone family. While your iPhone XS and earlier require a simple long-press of the shutter button to activate burst mode, that action now triggers QuickTake, Apple's new way to shoot video directly from photo mode. Burst mode's functionality has simply moved elsewhere.
To activate burst mode on iPhone 11, 11 Pro, and 11 Pro Max, swipe left on the shutter button and hold to shoot in burst mode. Just like before, you'll see the number of photos taken so far. The only difference is now this number appears in the shutter button, rather than just above it. Simply release the shutter to stop shooting.
Just make sure to do it fast. Holding down too long will engage QuickTake, blocking you from shooting in burst mode.