A clear difference is that in CVT a precursor is inside the growth chamber/tube/ampoule with the sample, while in CVD the precursor is injected into the growth chamber/tube from outside.
Chemical Vapor Deposition (CVD) is a process used to deposit thin films and coatings onto a substrate through a chemical reaction of vapor-phase precursors.
Chemical Vapor Transport (CVT) with a zone furnace involves growing bulk crystals by transporting material in vapor form from a hot zone to a cooler zone where it crystallizes. It's used for producing high-purity, single crystals of materials for research and development.