Please help me download IOS 11.0 to my IPhone

Hi - sorry, but you can't. You can only get the most up to date version which for your phone is 12.4.4.

Keeping in mind that, as helma145 stated, your iPhone model 6 cannot support iOS versions beyond 12.5.1 (because of hardware incompatibility), see this support article for help:--> If your iPhone, iPad or iPod touch won’t update

If the issue persists, update it using a computer running iTunes (PC) or iTunes/Finder (Mac).

Regards

Giulio

Not correct.

The latest version for an iPhone 6 is iOS 12.5.1