My local library offers a library app called Libby. It is connected to libraries around the US. It is both a reading app and an audiobook app. I use an Android phone so I don’t know if there is an Apple version out there. Download from the Google Play store, find you local library or libraries you have library cards for, add your library card and viola. You may now download library ebooks and audiobooks. I haven’t listened to any audiobooks yet, although the two samples I tried were clear and sounded really good.
I left a review of The Bone Witch, one of the first books I downloaded. Browsing is very easy, you can search directly or by genre, books and or audiobooks. All in all a great little reading app.