Web App Manifest

The web app manifest provides information about an application (such as name, author, icon, and description) in a simple document.

It's primary purpose is for creating progressive web apps: web applications that can be installed to the homescreen of a device without needing the user to go through an app store (along with other superpowers such as being available offline and presenting users with push notifications when application content changes.) - Mozilla Developer Network

php artisan pwa:manifest

This generator will help you setup your manifest.json file by asking you questions and generating the proper manifest.json file.
You can go ahead and modify the file manually.