reference pages for the meta seo inspector Google Chrome extension.
about viewport meta tag
Tells the browser that this webpage is optimized for mobile, changes the logical window size used when displaying a page on mobile browsers.
Include width=device-width to match the screen's width in device-independent pixels, and please ensure your page is accessible by not disabling user scaling.
The advised parameters to correctly support responsive design is the following:
<meta name="viewport" content="width=device-width,initial-scale=1">