Interestingly, the answer to this is a little tricky – apparently it works if you have Amazon Music (either through Amazon Prime or on it’s own), but not if you have Spotify!
If you have Amazon Music, follow the steps below:
1. Make sure the playlist you want to add the song to already exists. If not, tell Alexa to create a playlist, and name it whatever you’d like.
2. Once you’ve created the playlist, ask Alexa to play any song or album to add it to your newly created playlist. However, the song you want to add must be playing at the time – if it’s not, Alexa can’t add it to the playlist.
I tried to do this using Spotify, and I was told that adding songs to Spotify playlists was not supported at this time. Here’s to hoping Amazon and Spotify add that feature in the future!