This article will show you how to update the iOS operating system on iPhone or iPad without connecting to a wireless network (Wi-Fi). This can be done using iTunes installed on your computer.
Steps

Step 1. Connect your device to your computer
Connect the charging cable to your device and to your computer's USB port.
The computer must be connected to the internet

Step 2. Launch iTunes on your computer
To do this, click on the musical note icon on your desktop.
- Update iTunes if needed.
- If you don't have iTunes on your computer, download and install this program.

Step 3. Click on your device icon
You will find it at the top left of the page (below the menu bar).

Step 4. Click Check for Updates
This option is located in the right pane under a section that has the same name as your device.
If the operating system does not need to be updated, a window with a corresponding message will open

Step 5. Click Download and Update

Step 6. Click Accept
By doing this you agree to the terms of use of the software; the process of downloading and installing system updates will begin.
- When the updates are installed, the Apple logo will be displayed on the screen. Do not disconnect the device from the computer during the update process.
- Typically, it takes 40-60 minutes to update the system; you can follow the progress of the process in the iTunes window.

Step 7. Enter the password on the device (if required)
The operating system of the device is now updated to the latest version.