If you are away from home Wifi with you iPad and don’t have a cellular connection on the iPad you can use your iPhone to connect the iPad to the internet by creating a personal hotspot.
On your iPhone go to Settings>Personal Hotspot and turn it on. Note down the Wi-Fi password just below the On/Off switch.
On your iPad go to Settings>WiFi. From the list of available WiFi networks visible find the name of your iPhone and tap on it. Enter the password you have noted down and press Join at the top left of the screen. You will now be connected to the internet via your iPhone.