Adaptor

you can use this Buy 20W USB-C Power Adapter - Apple

but you can also just use an old charger and cable if you have one

The newest (Apple) power adapter that fit the new USB-C to Lightning cable is the 20W USB-C power adapter (and it is compatible with your iPhone 11).

Hint: you can still use the "old" USB to Lightning cable with the "old" 5W USB power adapter. It charges your iPhone 11 slower, because it does not even enable fast charge, but it works.