Web App in full screen mode build option?

Hello, is it possible to build your web app with options to run in full screen (standalone) mode in the browser like many PWA apps?

Usually I would add this into header and update manifest.json but I have no clue where to add these lines before I run a new build for web app. App is hosted on appgyverapp.com.

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

You can modify your web app files if you download the build. Other than that there is no way to enable such options now.