Today my young boy changed/ created a passcode for my wifi. He doesn't know what it is and neither do I. how can I get back my wifi?
Normally a WiFi password is set in your WiFi Router. If that is where he changed it, you need to look in the WiFi Router owner's manual to find out how to reset the router to factory defaults. Sometimes a router has a reset button you hold down while plugging in the router. Sometimes you just hold down the button for several seconds. It depends on the brand and model.
If the change was made in your iPad, go to Settings-WiFi and look for a blue arrow to the right of the WiFi network name. Press the blue arrow and you should see a screen with "Forget this Network" at the top. Pressing there should eliminate the problem and let you start over.