Do you need the permission of the original artist to make a cover of their song? And I'm talking about making a cover and releasing it on your album or something (not just some riffs on YouTube). Not that Im doing this, just curious how this stuff works... Thankya.
Yeah you need permission to record someone else's song. I don't know all the legal formalities of how you physically do this but I'm 100% certain you need their permission. I think you can play cover songs live (at gigs etc) to your heart's content but if you put that track on your album without permission you'd get kneecapped or something.
Yep, you need their permission and you'll need to cite their name as the person who wrote it in the sleeve notes.

Again, not quite sure how you do this. If youre talking about releasing an album then i would have thought youd be signed. Your management will (or should) know how to go about this