Do I have to pay for Apple Music to sync across devices?

DuskSky wrote:

Thank you for that solution. I realized that I have used the purchased option in the past to download music onto my other devices. My problem, actually, is sharing music I have uploaded from CD with my other devices.

In that case, the 2 options are:

1. Subscribe to Apple Music or iTunes Match to get access to the iCloud Music Library feature or
2. Use the direct Sync feature to transfer music from iTunes on a computer to an iOS device via a USB cable or Wifi

You will need to make sure Sync Music is turned off as counter-intuitive as that seems. Open Preferences in iTunes or the Music app if using Catalina, and make sure Sync Music is turned off.

Do the same on your iPhone in Settings->Music.

See here for steps to get to the option: Turn on / off Sync Library with Apple Music - Apple Support

Then follow the steps here to sync via USB: Use iTunes to sync your iPhone, iPad, or iPod with your computer - Apple Support

A third partial option when all devices and the computer that holds the music library are connected to the same Wifi network is Home Sharing: Use Home Sharing to share media from a computer to other devices - Apple Support

Home Sharing lets other computers and iOS devices devices access an iTunes library stored on a computer. You won't be able to copy over songs from the computer to iOS devices with this method however. Just access and play them while the device and computer are connected to the same Wifi network.