Can i uppdate my iphone 6

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 12.5.6.

If you are using IOS 11 as your profile shows, you can update to IOS 12.5.6 by following the instructions in the articles posted above.