How do I sync my iTunes to my iPhone?

Hi HopeZiarko,

Thanks for using Apple Support Communities. When syncing playlists to your iPhone using iTunes, be sure to select every playlist that you want on your iPhone including ones that have been synced previously. As explained in the following section of Use iTunes to sync your iPhone, iPad, or iPod with your computer - Apple Support, any unselected playlists are removed.

"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."

All the best.

See Recover your iTunes library from your iPod or iOS device - Apple Community.

tt2