This article explains how to use Safari parental controls. Instructions apply to iPhones and iPod touches with iOS 12 and later, iPads with iPadOS 12 and later, and macOS Catalina (10.15) and later.
How to set restrictions on Safari (parental controls)
The Parental Controls available for Safari on iPhone are part of Screen Time. Screen Time does more than just control Safari; it also helps you set limits on how you use the device. To use it to control Safari on iPhones and iPod touches, follow these steps:
Tap Content & Privacy Restrictions.
Set the Content & Privacy Restrictions slider to on/green.