#1 Upload your mp3 file to your media gallery. Under the edit, copy the URL of your mp3 file.
#2 Make a popup player Elementor template with an audio player use standard html format for this. See Link Here
<audio controls> <source src="horse.mp3" type="audio/mpeg"> Your browser does not support the audio element. </audio>
#3 Save our template and set the conditions to show entire site but do not set any triggers or advance options.
#4 Create a button and use the dynamic tools to call your Elementor popup. This will fire your audio player anywhere you need it on your site even a blog post in Gutenburg . (see test below)
We hope this helps you create a cool MP3 player on your site. Please smash the like button on the way out.