Enable parental controls.
You can find parental controls on iOS devices in Settings > General > Restrictions. Here, you can turn off some apps that come with the device, such as Safari (web browser), iTunes Store, and the dreaded In-App Purchase. Depending on your child’s age, you may not want them to have internet access. If so, just turn it off. The Safari app will not show up on the home screen. Next, is “Allowed Content.” These are basic filtering options on music, movies, internet sites, etc. Do not think however, that this is a catch all; some sites with highly inappropriate content may sneak past these filters. Lastly, you can adjust the “Privacy” for the device. Most notable here is “Location Services.” When enabled, this allows various apps to use the device’s GPS antenna. For example, if Location Services is enabled for the Camera, every photo snapped will have a GPS location from where it was taken. If you post that photo online, anyone can find that data and know exactly where it was taken. This could raise security concerns with regards to stalking or abduction.
Protect the Restriction’s password from your child, as well as the iTunes password. You should be the gatekeeper to all the apps that are installed on the device, but only after you have researched the app and approved it.
If the device is an iPhone, in addition to the controls mentioned above, your wireless carrier also has parental controls that can: Block calls and texts, limit texting and data usage, limit phone use by time of day, view a list of all the applications installed on your kid’s device and which of those apps they use the most, explore the contacts your kid has made, content filtering, or use their GPS to know their whereabouts right from your wireless phone.
Check with your carrier to see what options they offer.