I haven't tried this for probably a couple of years but I used to be able to go into one of my playlists, click share and there was an option to send directly to another Spotify user, and it would go to their Spotify inbox. The only options I see now are Facebook, Twitter, etc and, of course, copying the playlist link.
Mac Desktop Spotify version: 126.96.36.1998.g9064793a
Mac OS: Mojave 10.14.3
Solved! Go to Solution.
You're welcome, @stukan0000.
Let me know if you need help with anything else :)