You may host audio somewhere online such as at archive.org, get the mp3 URL, and link to it within your post. This is perfect for including a recording of yourself reading your poem.
As you will see in this video, others will be able to tap the link with the headphones icon and listen. Depending on where the file is hosted, it could take several seconds for the audio to start playing after tapping the link. It will play “inline” without navigating away from your poem.
Alternatively, you may simply paste a link to your audio on SoundCloud, Bandcamp, or other audio service. But, then the inline audio feature will not work.
We like archive.org because of the fact that it has been around for many years and is known for archiving everything on the web. Plus, you will get the plain .mp3 url if you upload there.