What was the name of the Beetle's convertible version?

The Beetle’s convertible version was called the Cabriolet.

“Cabriolet” is the traditional automotive term Volkswagen used for the open-top Beetle body style. The car retained the Beetle’s basic rear-engine, rear-wheel-drive layout but replaced the fixed roof with a folding fabric top and added structural reinforcement to preserve rigidity.

Karmann built the Beetle Cabriolet at its facility in Osnabrück, Germany. Production began in 1949, and the model became one of the best-known convertible derivatives in automotive history. Its four-seat layout and familiar rounded body made it more practical and recognizable than many small two-seat sports convertibles.

The answer is not “hatchback,” “sedan,” or “coupe.” Those terms describe other body-style arrangements: a hatchback has a rear liftgate, a sedan has a fixed enclosed passenger compartment, and a coupe is generally a fixed-roof car. Volkswagen produced the final Beetle convertible in 1980.