OK, I assume you mean you are thinking about subscribing to Apple,e Music on your PC via iTunes. Once you subscribe and turn on iCloud Music library in iTunes, all your music will be uploaded to the cloud so you can listen to it on any device. You will no longer need to (nor can) sync your library to an iPhone with iTunes (as I assume you have done in the past). There is no way I or anyone else can guarantee there will be no problems. That is why I suggested you backup your current library (and have it available if you unsubscribe).
Join Apple Music on your iPhone, iPad, iPod touch, Mac, or PC - Apple Support
And see the 'On your PC with iTunes for Windows' section in:
Turn on Sync Library with Apple Music - Apple Support'