I have iPhone 6 that have iOS version 12 and I want to update the latest updates but is no showing me an update

If I remember, the iPhone 6’s last software update was iOS 12.5.7. So if your iOS 12 was iOS 12.5.7., then you can’t update it any further as the phone doesn’t have the requirements to update further.

An iPhone 6 cannot update past iOS 12. If you need a newer iOS version, you will need a newer phone.

The iPhone 6 is obsolete. It can not run anything later than iOS 12.

The iPhone 6 can be updated to iOS 12.5.7, no further.