React Native App Only Using Webview?
If you're just using a webview inside a RN app you're probably better off just building a PWA and having users install it to their mobile device home screen (or just having them go to the website and make the website responsive). You're basically nullifying everything that's beneficial about a RN app by just using a webview. I also doubt that an app that only shows a webview of another website would make it past the review process of the App store. So I'd recommend strongly against this.
More on reddit.comHow do I login to a react native webview
React native and web-view
You can do JavaScript injection which can basically modify anything in the browser. HTML, CSS, run JavaScript functions to do whatever you want. You can also write a window.postMessage script in your webpage and listen for posted messages in RN by the onMessage function. Should just google it, there'd a lot on the web with examples.
https://stackoverflow.com/questions/52569195/injecting-custom-javascript-into-react-natives-webview
https://stackoverflow.com/questions/56737292/how-can-i-send-a-message-from-the-webview-to-react-native
More on reddit.comWebView in React-native. Few problems I've encountered. Any help would be highly appreciated
Videos
» npm install react-native-webview