What does it mean that delegation to environment?

Your environment can enforce behaviors that willpower alone cannot sustain.

Example: You decide to read more and scroll less. For three weeks, you rely on discipline — picking up the book instead of the phone. It works until a stressful Tuesday when the phone wins. Then you move the phone charger to the kitchen and place the book on your nightstand. Now reading is the default and scrolling requires getting out of bed. You didn't become more disciplined. You delegated the enforcement to your environment.

Try this: Choose one behavior you want to increase and one you want to decrease. For the behavior you want to increase, reduce the number of steps between you and the action to one or zero (place the guitar next to your desk, leave the journal open on the table, set the running shoes by the door). For the behavior you want to decrease, add at least two steps of friction (move the app to a folder on your phone's last screen, unplug the TV after each use, keep the snack food in an opaque container on a high shelf). Run this configuration for five days and note what changed without any additional willpower.