The veteran striker moves to Old Trafford on a one-year deal with a package worth £200,000 per week.
Cavani, 33, was released by PSG at the end of last season and has seen transfers to Atletico Madrid and Benfica fail to materialise over the course of the summer.
United held talks with the Uruguayan earlier in the window but made a late swoop this week to land his signature in their desperation to bring in new recruits.
His arrival raises question marks over United’s transfer strategy but there is little doubt the club have landed a player who possesses world class pedigree.
“Manchester United is one of the greatest clubs in the world, so it is a real honour to be here,” said Cavani. “I’ve worked really hard during the time off and I feel eager to compete and represent this incredible club.
“I have played in front of some of the most passionate supporters in football during my career and I know that it will be the same in Manchester.
“I cannot wait to experience the Old Trafford atmosphere, when it is safe for the fans to return.
“I look forward to continuing to write my little story inside the book of football and I know that’s why my focus has to remain the same as always – work, work, work.
“I have had a conversation with the manager and this has increased my desire to wear this beautiful shirt.”
Manchester United are looking to plot their path back to the top. Ole Gunnar Solskjaer has already brought in Donny van de Beek but Jadon Sancho remains Manchester United’s number one target.
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Ole Gunnar Solskjaer said: “Edinson is an experienced ultimate professional who always gives everything for his team.
“His goalscoring record for club and country is fantastic and we are delighted to sign a player of his calibre.
He’ll bring energy, power, leadership and a great mentality to the squad but, most importantly, he’ll bring goals.
He has had a brilliant career so far, winning trophies at almost every club he has played for, and he still has so much more to give at the highest level
Is Cavani a good signing for United? Have your say below.
Cavani’s arrival looks to all but signal the end of Odion Ighalo’s time at the club, with the Nigerian’s loan spell set to expire in January.
This was just one of several transfers United were negotiating on in the final hours of the window, with Alex Telles and Amad Diallo also completing moves.
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