Mourinho, who was in Monaco to watch the Grand Prix practice yesterday, has 12 months left to run of a four-year deal.
His first season, which brought the club three trophies, has helped convince the board that he is the man to take them back to the top.
He has formed a close working relationship with United’s vice chairman Ed Woodward and they are planning a £200million summer spending spree.
The Portuguese has insisted that United must spend big if they want to close the gap on the top four after finishing sixth.
He earns close to £20m a season and United would like to have the deal complete by the time they resume pre-season training.
And Mourinho has told executive vice-chairman Ed Woodward to get to work over their summer transfers.
“He knows since March who I want, what I want, how much I want – he knows everything since March,” Mourinho said.
“And now it’s for him to work because he will have holidays in August, and in August I am working.”