A standalone propane patio heater is mostly hollow steel and easy to carry, but the propane tank underneath has real rules for safe transport. Separate the two and follow tank guidelines and this is a quick job.
Pro tip: If you are moving more than a short local distance, it is often cheaper and safer to sell the full tank locally and exchange for a fresh one at your destination rather than transport it.
Watch out: Never transport a propane tank on its side or in a sealed, unventilated trunk; both increase the risk of a leak building up in an enclosed space.