When an object enters play copying another object, it copies all ‘base’ characteristics. Other than copy effects, effects that are applied to the original are not copied. Also, unless the effect that copies the original says so, the copy will not have any additional types or colors.

Which brings up to Phyrexian Metamorph. As a Phyrexian Metamorph enters play its controller chooses an artifact or a creature in play for he Metamorph to copy. The Metamorph will then enter play as a copy of this chosen object. If it copies a creature, the Metamorph will be an artifact creature. This is because the Metamorph’s ability specifically mentions that the Metamorph will have the type ‘artifact’ in addition to its other types.

However, if the Metamorph copies a noncreature artifact, then the Metamorph will simply be an artifact and not a creature. It does not matter that the Metamorph’s type line says creature.