Many social networks allow people to ‘check in’ each time they tweet or post an update. This can mean that strangers can see where your child, especially if their profile isn’t private.
To turn off location settings on Twitter, click on your child’s profile picture at the top right-hand side, scroll down to ‘Settings and privacy’, then to ‘Privacy and safety’ on the left-hand side, then untick the checkbox that says ‘Tweet with a location’. You can also press the button that says ‘Delete location information’, to clear information about where they’ve been in the past. You can also turn the location off on their actual mobile phone.