While using the iPad Pro I decided to add a few sites to the home screen. It’s not something I usually do on the iPhone, although the same thing works on the iPhone too:

Press the share button (the one in the middle at the bottom) to show the options panel:

Choose “Add to Home Screen”:

Now you’ll see an app on the home screen with the site favicon.

Clicking it will simply open the site in Safari.

But if you add this meta tag to the page:

<meta name="apple-mobile-web-app-capable" content="yes">

Clicking the app icon will open the site in full screen:

This works on the iPad as well:

This will help you save screen real estate, as the Safari UI would be useless, and will also make the overall app use experience much better.

Of course this has to be supported by the site/app developers, otherwise you can’t make it full screen.