After creating your Bubble app, you will have 2 versions. One of them is the "development" version where you will make improvements and changes to your application. After testing the changes you made in this version, you can deploy the final version of the application to the "live" version of your application. The "live" version is "read-only" and your users use this version of your application. So you need to make sure that everything works correctly.

To preview the "development" version of your application, add "/version-test" to the end of the root URL in the URL address. To preview the "live" version, you can add "/version-live" or you can preview directly from the root URL.

To switch between versions via the app editor, you can use the dropdown menu on the top right corner of the editor as in the screenshot below. You can also use the "Deploy to live" option in this menu to move the "development" version of your application to the "live" version.

You should know that the database is also divided into "development" and "live" versions. Even though the database structure is the same, the data will be completely different. To move the data between each other, you can switch from the "Data" tab to the "App Data" sub-tab and click on "Copy and restore database". Then you can use the features offered to you from the window that opens.