The Belgium international scored 25 goals and registered six assists in the Premier League for the Merseyside club, and his form for Ronald Koeman's side has seen him attract interest from the Red Devils and Chelsea.
Chelsea manager Antonio Conte had identified Lukaku as a priority signing in the summer transfer window. Chelsea believed they were in the pole position for the striker's signature.
However, Jose Mourinho's side have hijacked the deal and the 24-year-old is now heading towards Old Trafford after they agreed a £75m ($97.3m) fee with Everton.
United were in the market for a striker after Zlatan Ibrahimovic was released, with his contract expiring in the summer.
Hughes is confident that Lukaku will join United this summer and can replace the Swedish striker for the Red Devils.
"In fairness to the boy, for a number of years, he has been scoring regular goals at the top level of British football," Hughes said, as quoted by the Manchester Evening News.
"It [United] will be a different challenge for him. Everton are a good club – I've played at both clubs.
"Everton are very much a family club. United, clearly since I left, it's gone on to become even bigger on the world stage and it's a huge entity now.
"Maybe he will find a little bit of a difference in that, but his day-to-day work will be similar and I'm sure he will be a great success there.
"It's been in the offing for a while it seems. There's been a lot of discussion in terms of which club he was going to go to.
"There's been a lot of talk about Chelsea but it looks like he's going to go to Manchester United. Given that Manchester United have lost Zlatan (Ibrahimovic), they clearly had to address that and they have gone for Lukaku."
Hughes, who played as a forward for top clubs like United, Barcelona and Bayern Munich, is well aware of the attributes needed to be a striker at Old Trafford. The Welshman also played for Chelsea, Everton, Southampton and Blackburn Rovers.