Short answer
PWABuilder creates a Trusted Web Activity, which needs a web manifest, ideally a service worker, and a Digital Asset Links file on your domain; without verification the app shows a browser URL bar. If you can't change the site, a WebView-based URL to App converter such as Website to App builds from any https URL with no site changes, from your phone.
When PWABuilder is the better choice
You own the domain, your site is already a solid PWA, and you rely on Google sign-in or web push. Then a TWA from PWABuilder is a great fit. See WebView vs TWA.
When a WebView build is better
- Your site builder (Wix, Squarespace, a hosted shop, Bubble) doesn't let you upload
/.well-known/assetlinks.json. - You need control over where links open, file uploads, downloads or payment-app handoffs.
- You want to build from a phone without a computer.
Sign-in note
Moving from TWA to WebView means Google sign-in needs a Custom Tab flow — read this first if your site depends on it.
FAQ
Is PWABuilder free?
Yes, PWABuilder is free and open source from Microsoft.