How would you do the zoom out so it will fit the screen
normally you add:
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
to the <head> region of your html.
you can also use css to set the body width (100%).
this, of course, only works if you're creating your own html content. if you're just using a webview to browse public websites, you should know that 1) the hard work has already been done for you with chrome, and 2) webview is only a subset of a browser. there are functions which work in a real browser that do not work in a webview.
as for webviewsettings, you include the webviewsettings library in your project and initialize it after initializing your webview. (note: this setting is deprecated, so if it still works, it could un-work whenever google updates the view,which is a few times a year). in any case, my understanding is that it is tied to screen density. i believe it would be an effort to ensure a similar viewing experience of your content across devices with varying screen sizes. i do not believe this means you necessarily see the page fitting the screen. i'm pretty sure that is controlled by the instructions mentioned above.
since i don't know what your intentions are regarding webview, there's not much more to say. except a webview is not a browser.