Updating my phone

Use Ethernet Via a Computer:

Using a Computer:

Start with attempting an update through use of a computer. Go Here: Update your iPhone Using a Computer - User Tip.

If WiFi is of no success...

Use Ethernet:

In the computer, you would connect it through Ethernet, going directly into your router. For a Mac (or PC) that does not have Ethernet, this would be the adapter to use: Belkin USB-C to Gigabit Ethernet Adapter - Apple

I would recommend that you try updating your phone via iTunes rather than OTA (Over the Air).

Try restart your phone