Playlist missing

Hello Pedraza07,

Thanks for posting in Apple Support Communities. How do you usually add songs and playlists to your iPhone? That may help narrow this down.

If you use a computer to sync your playlists, be sure to select the playlists that you want to remain on your iPhone each time you sync. This is because deselecting songs or playlists is how you would remove those that you don't want. These steps from Use iTunes to sync your iPhone, iPad, or iPod with your computer - Apple Support may help further.

"Sync or remove content using iTunes

1. Open iTunes and connect your device to your computer with a USB cable.
2. Click the device icon in the upper-left corner of the iTunes window. Learn what to do if you don't see the icon. 
3. From the list under Settings on the left side of the iTunes window, click the type of content that you want to sync or remove.* To turn syncing on for a content type, select the checkbox next to Sync.
4. Select the checkbox next to each item that you want to sync.
5. Click the Apply button in the lower-right corner of the window. If syncing doesn't start automatically, click the Sync button."

Kind regards.