Hi there, @marsgoals… if you want to view your design on a phone, you can navigate to the app’s url via the phone’s browser.
That being said, you have other options that will let you see how your app is rendering on a phone from within your laptop’s browser. The first option (and I’m sure you know about this one already) is Bubble’s responsive tab that lets you easily switch between screen sizes. Another option is within the Chrome browser itself (and I’m sure other browsers have it, too), and I showed another user that option in this post…
Hope this helps!
Best…
Mike