GPS TRACKER is the best way to know the location of your family at any time. 

This app allows you to find out what they are doing in the moment, and where they have been over the course of the day. If you want to know where your kids are, for example, all you need to do is select the location of the child, and click 'Follow'. You can also find out where your wife is if you happen to be in the same situation. 

As long as they are online, and using their smartphone to connect to the internet, you can track them.