Sancho will complete a £72.9million move from Borussia Dortmund after the Euros with a fee and personal terms already agreed.
His arrival ends United’s three-year pursuit of him, with Ole Gunnar Solskjaer convinced he can solve the club’s long-standing problem position on the right wing.
Sancho will sign a five-year contract with the option of a further 12 months and will link up with England team-mate Maguire at Old Trafford.
Maguire hopes his arrival can see United close the gap to Premier League champions Manchester City, saying: “Jadon is a top, top player. He has exceptional talent even though he is still really young, although he has played so many games.
“I don’t know if it’s confirmed or not, but I think they are nearly there in terms of signing him at club level. If he does sign and when he does sign, I’m sure he’s going to have a great career for Man United and be a big part of us being successful in the future.
“I’ve been really impressed with the way he has been working in training. He is really putting a shift in day in, day out. He has some great talent. He is scoring goals in the five aa sides and so on. He’s a great lad.”
Sancho has had to spend the majority of the Euros on the side-lines for England, with Gareth Southgate preferring Phil Foden, Raheem Sterling, Jack Grealish and Bukayo Saka to him so far.
Maguire believes he can still have a major impact at these finals, adding: “He has great experience in these big games. We’ve obviously got some exceptional talent in his position in this team so he will bide his time and be patient and be ready when his opportunity comes.”