To turn on Wi-Fi and connect to a Wi-Fi network, from the home screen, tap Settings.
Tap Wi-Fi.
Tap the "Wi-Fi" toggle to turn on or off. Note:To optimize battery life, turn Wi-Fi off when not in use.
With Wi-Fi turned on, tap the desired Wi-Fi network. Note: To connect to a hidden or unbroadcasted Wi-Fi network tap Other. You will need to enter the Network Name (SSID), Security, and Password (if necessary) to continue.
If prompted, enter the Wi-Fi network password, then tap Join. Note: Secure networks will display with a Lock icon.
When iPhone is connected to a Wi-Fi network, the Wi-Fi icon will be displayed in the Notification bar. Note:Data transmitted over a Wi-Fi network does not count toward your AT&T data plan, and will not be billed.
To remove a saved Wi-Fi network, tap the Information icon 'i'.
Then tap Forget This Network. Note:Learn more from Apple support article: Connect to Wi-Fi on your iPhone. If you can't connect to a Wi-Fi network, get help.