You need 4 things to make a PWA: HTTPS hosting, a service worker, a properly configured index.html file, and a web app manifest.json file. The examples below are geared towards React but are similar for any framework.
A challenge in configuring your app is understanding the difference in how iOS and Android use the meta tags in index.html and the web app manifest. We’ll explain how each option is used below.
One painful part to this process is creating the massive number of splash screens for iOS: one for each screen size and orientation you want to support, otherwise users will see a white screen while your app loads.
... read the whole story at blog.truthlabs.com.