There are a number of different ways to configure a wireless network. One of the most popular is just to set a password, but you can also filter a router to ensure only specific devices access the internet.
In order to do that, you need MAC or Wi-Fi addresses from each device. And sometimes they can be difficult to find.
In order to find them on an iOS device, you need to open the Settings App, and then open the General tab. Then, you need to press “About”.
Down the bottom you should see a string of numbers after the words “WiFi Address”. This is the number you’ll need to type into your router’s software.