How to upgrade my phone to 13.0

iOS 13 is not available for download anymore. iOS versions 15 and 16 are.

You have an iPhone 6 Plus and your are not going to be able to update that model iPhone any further than iOS version 12.5.7. You will need a newer model iPhone to update to iOS 15/16.

Axel F.

Here's some simple steps on how to upgrade your iPhone's software.

Go into Settings >> General >> Software Update. Press the Install/Update button. These updates can take a while so be prepared to wait a little.

Refer here for more information: About iOS 13 Updates