In iOS 14 or later, you’ll find Deliveries in the row of color app icons. If you don’t see it there, scroll all the way to the right, tap “More”, then find Deliveries there. If necessary, tap the “Edit” button, and make sure the switch next to Deliveries is turned on. If you use it often, tap the green + button to add it to your Favorites.
If you still can’t find it, there is a bug in iOS 14 that can cause apps to disappear from the share sheet when an update is installed. Restart your iPhone or restart your iPad and it should appear again.