After United scored a record low of 44 goals in 38 Premier League matches last season, bolstering the attack was a clear priority for manager Ruben Amorim.
Although not a traditional centre-forward, Cunha has scored 27 goals in 65 league games for Wolves over the past two seasons.
Winger Antony and striker Rasmus Hojlund have arrived at Old Trafford for big transfer fees in recent years and struggled to adapt to the Premier League.
Newcastle United, who will play in the Champions League next season, were interested in signing Cunha.
“United are lucky they still have their historic appeal and reputation as a club, so players of the Brazilian’s quality and potential want to move there,” former England midfielder Fara Williams told BBC Sport.
“There is no doubt he improves the squad.”
