The iPhone can browse the Web over your cellular connection, but whenever possible, you should connect to Wi-Fi to save on data costs. Wi-Fi is usually faster and more stable than a cell connection, as well. Every time you connect to a new wireless network -- when you first buy your phone, when you replace your router (or change its password), when you visit a friend's house and so on -- you need to pick a network in the Settings app. Afterward, your iPhone reconnects to the network whenever it's in range.
Connect to a Wireless Network
Open the iPhone Settings app and tap Wi-Fi. If the Wi-Fi slider is off, tap it to switch it on.
Tap the name of the network you want to join. If you don't know the name of the wireless network in your home, look for a sticker on the back or bottom of the router.
The i icon by each network opens extra network information and settings, such as the setting for a static IP address. Most people never need to touch these extra settings.
Enter the password for the network and tap Join. Unlike some other devices, you don't need to know or input the type of security your router uses when picking a network off the list.
Open networks in public places often don't require a password. Tap a network that doesn't show a lock icon to connect.
Some networks -- such as those in hotels -- use a separate login system rather than requiring a Wi-Fi password. If a network requires this step, the login page appears in a browser window after you connect.
After the connection is made, the network icon in the status bar changes from displaying your cellular data connection — such as 3G, 4G or LTE — to displaying the Wi-Fi connection strength.
To change to another network, just pick it from the list. The iPhone remembers the passwords for multiple networks, so you won't have to re-enter them every time you change networks.
If You Don't See Your Network
The iPhone usually shows every network in range, except for hidden networks. If your network doesn't show up in the list and you're sure it's running, enter it manually.
Tap Other at the bottom of the wireless network list and enter the network name (SSID) by hand.
Tap Security and pick the security type for the network. As of iOS 8, the iPhone supports WEP, WPA, WPA2, WPA Enterprise and WPA2 Enterprise security systems. For open networks, choose None. After picking a security setting, press Back.
If you're setting up a new home network, WPA2 -- also called WPA2 Personal -- is the most secure choice. Some old devices, however, only work with the original WPA. Many routers offer simultaneous WPA and WPA2 security to help with backward compatibility.
WEP is a severely outdated system that offers little protection.
Enter the network password and tap Join.