iOS has a built-in feature that lets you quickly share Wi-Fi passwords for devices by bringing them closer to each other. It uses Wi-Fi, Bluetooth and each user's Apple ID to securely share the password between devices.
Sharing your Wi-Fi password can be a frustrating endeavor. Having a complicated Wi-Fi password with letters, numbers, and special characters can be a real burden for your Aunt Edna visiting on Thanksgiving. From iOS 1
First, make sure Wi-Fi and Bluetooth are enabled on both phones. You can check this under Settings> WLAN or Settings> Bluetooth. Simply move the slider to the "on" position.
Second, make sure you both have the other user's Apple ID in the "Email" section in Contacts – otherwise it will not work! Incidentally, this method works even if both devices use the same Apple ID.
Finally connect one of the devices to the Wi-Fi.
On Go to the disconnected device> Settings> Wi-Fi.
Tap the name of the network you are using If you want to join, you will be prompted to do so Enter password.
Unlock the other iOS device and hold it to the device that you connect. The already connected device will be asked to provide the Wi-Fi password. If you click "Share password", the connected device receives the password and connects.
Done! The password field on the second device fills in the password automatically and establishes a connection.