This is how you create keyboard shortcut of long phrases on iPhone 11 Pro. It might also work in iPhone 11 and 11 Pro Max.
1. From the home screen Tap on settings.
2. Tap on General.
3. Tap on Keyboard.
4. Text Replacement.
5. Click on the + icon to add your replacement texts. After tapping on the + icone you will see 2 boxes, phrase and shortcut. Write what ever phrase you want in the phrase box and add a 2 or 3 characters of shortcut in the shortcut box and then save it.
That's it. It's done!