Sign up for Curbi (free), register your family's devices, and you're ready to rule your family's screen time remotely. You decide what to block (social media, YouTube), when to block it (say, at bedtime or after two hours of use), and which devices each of your rules apply to. Other cool features include the ability to instantly put your child's device in timeout and the app's weekly emailed report of each device's usage.
Available for iOs and Android