Patio Roofing Question - Transparent corrugated pvc covering
It will be (or had better be) polycarbonate or acrylic, not PVC, or it will die in the sun.

If you find it too clear to begin with, greenhouse suppliers have "paint on shade" and/or shadecloth, both come in white and in colors.

If all you want is shade, shadecloth might be a better choice than roofing, but of course it does not block rain. Shadecloth suspended above the glazing would likely do a slight better job of blocking heat than either paint or shadecloth laid right on the roofing.

Metal will be simply broiling hot.