Or, if you own both the Kindle and Audible versions of a book, you can switch between reading and listening simply by bringing up the onscreen menu and tapping the headphone icon the corner of the screen... (computershopper.com)
Also, a headphones icon appears in the notification area at the bottom of the screen so you can instantly get to you music, pause, skip track or end play completely. (pocket-lint.com)
Audiobooks show up in the ebook gallery with a headphone icon appended, and once opened you can tap to switch between the text and audio versions (the Kindle Oasis remembers which you were using last, and re-opens it in that state). (slashgear.com)