Hey there, EscobioS!
Thanks for reaching out to the Apple Support Communities! It sounds like you have an issue with your playlists being missing on your iPhone and need to update iTunes on your computer. For the playlist issue, make sure you have updated all devices you have, and make sure Sync Library is on. Learn more in this article about how to Turn on Sync Library with Apple Music.
For the issue with updating iTunes, here are the steps to Update to the latest version of iTunes.
We also recommend the steps here if you have issues updating on a PC If you can't install or update iTunes for Windows.
Let us know the rtesults and have a great day!