Parental control apps provide content filters, app management tools, screen time schedulers that are installed on each device. TAG offers install and support for robust filters and should be the first place to start, visit your local TAG for more details. The following are "off-the-shelf" filters that can be self-installed and managed by directly, or remotely by a parent or spouse.
Multi-device control/filter
Qustodio offers web filtering and app control on many device types, including: Android, Apple iOS/Mac, Windows, Kindle, Chromebook
Canopy Parental Control
From the makers of Netspark
Parental Control filtering that includes the option for image masking (blocking in-browser inappropriate pictures).
Screen Accountability
Partnership with Covenant Eyes providing screen monitoring sending screen shots to a trusted "chaver" (friend or spouse). Web filtering is available as an additional option.
Works best on Android (iPhone is limited)
Windows PC
Techloq provides the most robust filtering, including image masking, for Windows PC.