So I have been struggling with this issue for a while and thanks to the great support of WIX I managed to solve this and just wanted everyone to have this trick up their sleeves for every app or website you create using WIX Code and want the website to open up just like a fullscreen native app.
When a user adds your site to their home screen which I always recommend them to do if it is a app or something they will need often.
This is for iOS only but you can easily Google to the settings for Android.
1. Go to your Dashboard
2. Select the site
3. Click Manage Site
4. Go to SEO tab
5. Header Code - Meta Tags section allows adding custom Meta tags for the whole site
The above was a tip from WIX support and then you add the following text into the header form input field.
<meta name="apple-mobile-web-app-title" content="WIX Sweden" />
The above will add WIX Sweden as the title under the icon and it will be the favicon image that will be your apps icon on the phone.
<meta name="apple-mobile-web-app-capable" content="yes">
The above will make the website / web app open up in full screen, no more safari header or footer, just your newly created app in lovely full screen.
It is just awesome and will be very nice doing apps and applications in WOX Code and make them open in full screen.