Currently you are able to watch "The Avengers" streaming on Amazon Prime Video or for free with ads on Pluto TV. It is also possible to buy "The Avengers" as download on Apple TV, Amazon Video, Vudu.
The Avengers is a British television series created in the 1960s. It initially focused on Dr. David Keel and his assistant John Steed. Hendry left after the first series and Steed became the main character, partnered with a succession of assistants. His most famous assistants were intelligent, stylish and assertive women: Cathy Gale, Emma Peel and Tara King. Later episodes increasingly incorporated elements of science fiction and fantasy, parody and British eccentricity.