My iPhone can't connect to any networks for longer than a few minutes?

Whenever I try to connect either the Wi-Fi will not turn on at all or it can't find any networks. Everything else works fine and my Internet runs smoothly, I tried resetting the network connections, turning the phone off and on, backing up my phone but still nothing. I just want to know if I can fix this by myself or not.

I had the same problem.
Try going too Settings>General>Cellular>off
The Wi-Fi should stay connected. After a while you should be able to turn Cellular back on without it going off again. (It probably will happen again.)
If that dosen't work, then go to Settings>general>reset>reset network settings.
After that turn your phone back on then enter your password for your Wi-Fi and it should work.

Settings - General - Reset - Reset Network Settings

And then rejoin your wi-fiand try again. If it's one singular network unplug the router from power and plug it back in after 30 seconds to clear out any errors.