The classic answer everyone points to is Ylvis's 2013 song "The Fox (What Does the Fox Say?)" — but you asked about the wolf, and the honest answer is simpler: a wolf howls, growls, barks, whines, and snarls, depending on context.
Howling is the famous one — a long, rising-then-falling note used to communicate over long distances: rallying the pack, marking territory, or locating other wolves. Wolves also bark as a short alarm signal, growl as a warning during conflict, and whine or whimper in friendly or submissive interactions, especially between pups and adults or within close pack bonds.
If you meant it as the joke riffing on the "Fox" song, the punchline is usually "Awoooo" — since unlike the fox's sound (which the song plays for laughs as a mystery), the wolf's signature sound is genuinely well known.