If you have a smartphone and a mobile data plan, you should be able to create a mobile WiFi hotspot to share your 3G or 4G connection with your other devices.
Android
Open the Settings app.
Tap the More button at the bottom of the Wireless & networks section
Select Tethering & portable hotspot.
Tap Set up Wi-Fi hotspot.
Specify a network name and password and click Save.
Turn on the Portable Wi-Fi hotspot option.
iOS
Open the Settings app.
Tap Cellular.
Tap Personal Hotspot.
Tap the slider to turn it on.
You have the option to change the hotspot’s password.
Always make sure to protect your mobile hotspot with a strong password to prevent other people from using your data plan to connect to the internet. You should choose a password that’s at least 12 characters long, consists of numbers, letters, and special characters, and cannot be easily guessed. Avoid common passwords such as 12345QWERTY and don’t share your password with anyone else unless you’re willing to change it right after.
Keep in mind that your smartphone’s battery will deplete faster with a mobile hotspot active. How much faster exactly depends on many factors, including the number of devices connected to the hotspot and the type of mobile connection.