I want to update my iPhone

Assuming you have a compatible device, see: Update your iPhone, iPad, or iPod touch - Apple Support

And: If your iPhone, iPad, or iPod touch won't update - Apple Support

If the above Apple articles do not help, please post back with relevant information. 

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

abba131 wrote:

Watching mover and playing football

Can we assume you have already solved your tech support issue by merely posting the text above? If so, well done.