Turn on Wi-Fi on your iPhone
Go to Settings > Wi-Fi, then turn on Wi-Fi.
To join a network, tap one of the following:
A network: Enter the password, if required.
Other: Join a hidden network. Enter the name of the hidden network, security type, and password.
If appears at the top of the screen, iPhone is connected to a Wi-Fi network. (To verify this, open Safari to view a webpage.) iPhone reconnects when you return to the same location.