Sometimes you will find the iTunes Sync button greyed out or part of iTunes music library cannot be checked, or Add to device option greyed out so you can’t transfer music to iPhone. Listening to music on computer is not enough, so you want to import them to iPhone by iTunes so you don’t need to take a long time to download them again. You could purchase and download many albums from iTunes store.
After I plugged my iPhone into computer and got ready to sync music to iPhone, I found that the button Sync is greyed out in Summary.
I have 300+ songs in iTunes library on my Dell computer and wish to transfer them to my iPhone 11.