To play a song in the background of your slide show, do the following:
On the Insert tab, select Audio, and then Audio on My PC.
In the file explorer, locate the music file you want to use and then select Insert.
On the Playback tab, select Play in Background.
Tip: If you want to use music from the web, download it to your PC before you use it in a presentation.
Note: If you’re using PowerPoint Online, you can play music and other sound effects that you’ve added to your slides using the powerpoint desktop application, but you can’t add them from within powerpoint Online.
If you have the powerpoint desktop application, you can add sound effects there.
For more information, see Play music or other sounds in your slides.
Do you want to play multiple songs across multiple slides?
If your slide show is longer than one song, you can add more songs. However, if you find that you’re having trouble synchronizing the music with the slide show, you can use a third-party audio editing tool, such as Audacity®, to string the songs together into one file so they play continuously throughout the slide show.
Other related help content includes:
Video and audio file formats supported in powerpoint
Delete a music clip or another sound
Record a slide show with narration and slide timings
Play music and other sounds automatically when a slide appears
For people who use powerpoint for Apple Macintosh, see:
Video: Add audio that plays through your entire presentation
Video: Add multiple songs to your presentation