Can I update software without WiFi?

On a Mac with macOS Catalina 10.15, open Finder. On a Mac with macOS Mojave 10.14 or earlier, or on a PC, open iTunes.

If you have a PC, then download iTunes. You can do that from the Microsoft Store, and of course it's free. Link: https://www.microsoft.com/da-dk/p/itunes/9pb2mz1zmb1s?activetab=pivot:overviewtab

1. Connect your device to your computer.
2. Locate your device on your computer.
3. Click General or Settings, then click Check for Update. 
4. Click Download and Update.
5. If asked, enter your passcode. If you don't know your passcode, learn what to do.

Yes, you can set it to a PC / Mac and update it that way around.

Thanks!