Not able to edit song info, delete songs and add or remove artwork

My old iPhone 4, 5 & 6 don't allow me to delete songs from iTunes, edit song info, drag and drop songs or album artwork. The iPhone 4 lets me edit it on a different PC however on my main PC it won't let me edit anything, for my iPhone 5 it was letting me do it not long ago now it's having the same issue as the iPhone 4 and as for the 6 it's just the same issue as the 5. All the audios are read & write as well.