Neville believes Man United must make the signings if they are to be more competitive next season than last term.
Man United finished outside of the Premier League top four last season under interim manager, Ralf Rangnick.
However, with the appointment of Erik ten Hag as Man United’s permanent manager, Neville believes the Red Devils need to sign a centre-forward, central midfielder, full-back and wide player this summer.
“I think, to be honest with you, I don’t know which area needs strengthening fully until we know which players the new manager likes,” Neville told the club’s official website.
“We know the areas they absolutely need to actually strengthen,” he added.
“Central midfield is an absolute necessity. An absolute necessity. Manchester United needs midfield players.
“They also need a centre-forward. I know Cristiano Ronaldo is likely to stay and he’s an absolutely brilliant performer, but they need a centre-forward. Centre-forward is a must.
“I think there will need to be a wide player, just to beef up the squad, and I think full-backs are absolutely critical in the modern game. [There are] four full-backs there, it will be interesting to see which two, three or four of those are liked.”