A taxi is a vehicle that carries passengers for a fee. Taxis are typically owned and used by Muggles.
In 1994, the Weasley family ordered three taxis to come to the Burrow to pick up and transport them (along with Harry Potter and Hermione Granger) to bring them to King's Cross Station.
An unidentified Muggle driver owns a taxi. 24 Hour Car Service provides taxi services, along with Nicolicab, Rainbow Chariots and Taxis London.