Hi! You can do that in 2 different ways: Creating a Progressive Web App (PWA) or using Firefox extensions. The exact way will depend on the version of Firefox that you have.

Take a look at these links: 1. https://addons.mozilla.org/en-US/firefox/ (for add ons) 2. https://h2v.eu/app_install (for PWA)

Hope this is helpful! :)

Support for Site Specific Browser (SSB) and Progressive Web Apps (PWA) has been dropped in Firefox 86 (bug 1682593), it is no longer possible to use this feature in current Firefox releases.