Once your Vue.js application has been deployed to Firebase, you can access it by visiting the URL provided by Firebase in the terminal after running the
firebase deploy command.
You can also view your deployed application by visiting the Firebase Hosting section of the Firebase console.
You can test the chat functionality by opening the URL in multiple browser windows or devices and start sending messages from one browser window, and check if the messages are being displayed on the other browser window in real-time.
Also, you can check the Firebase Firestore database to make sure that the messages are being saved correctly, you can check the database by visiting the Firebase Firestore section in the Firebase console.
Please note that you may need to configure your Firebase Security Rules to allow read and write access for the chat messages in your Firestore collection.
Also, you may want to test the chat application on different devices and screen sizes to ensure that it is fully responsive and works well across different platforms.