How can I change title names/artists on iTunes 12.3?

Thank you, however I don't have, or have ever used Windows Explorer. I only use Safari on my iMac. Is there any other way around this?

Thanks for the reply. I followed your instructions but it was already in "Read & Write". I clicked it again just to be sure and then clicked on the gear icon below but the 3 choices (including Apply to Enclosed Items) were all in grey, which as you know, makes the user unable to choose any of them. The thing is, I can change the names/titles in iTunes but not to the ones I've purchased. You used to be able to do that before they reverted to the Cloud. Perhaps it has something to do with property rights, who knows.