Okay, finding Melody Anne's stuff for your ears is pretty straightforward, but which path you take kind of depends on what you're after. I went down this rabbit hole last year.
If you want the official, polished experience, Audible is the main hub. Almost all of her newer releases drop there first, and a huge chunk of her backlist—the 'Billionaire Bachelors' series, the 'Unexpected' books—is available. It's clean, reliable, and the narration is consistently good.
That said, I've also had luck with Libby through my local library. The selection is more hit-or-miss; you might find 'The Tycoon's Secret' but not the latest one. The waitlists can be long for popular titles, but hey, free is free. I'd start with Audible or Scribd for breadth, then check Libby for a specific title you're patient for. Her narrators tend to have that warm, slightly dramatic tone that works for her kind of contemporary romance.