You can use mobile data to download the latest version of iOS.
Before you begin: Make sure that you have a good cellular data connection and enough megabytes in your plan.
Follow these steps:
- Create a Hotspot from your iPhone. This helps to use the cellular data from your iPhone to connect to the web on your computer.
- Open iTunes and plug in your iPhone after that.
- In iTunes, click on the icon that represents your iPhone.
- Click on Check for Updates.
- Find the option to download and install iOS 13.
Your Mac/Windows will proceed to download iOS 13 using the Hotspot you created from your iPhone. iTunes will then install iOS 13 on your iPhone.
All the best with a fresh version of your iOS :)