Can i put my baby iguana in a 7' H x 3' D x 6' L habitat?

That would be a great grow out cage,and even and adult cage. By "items" the other guy means decor which is very important,because that is no small cage,you might even wan to consider cutting half off for now until he gets a bit bigger,because it will be a bit hard to catch the little guy and you don't want to chase him around and the cage stressing him out every time you want to handle or check him out. Add some decor to make him feel more safe and secure and maybe even multiple baskins and water dishes.