Woodward announced his intention to leave the club in the wake of the failed European Super League debacle before staying on beyond the end of 2021 following the sacking of Ole Gunnar Solskjaer.
Executive Co-Chairman Joel Glazer told Manutd.com: "I would like to thank Ed for his tireless work on behalf of Manchester United during his nine years as Executive Vice-Chairman and 16 years with the club.
"We are now looking forward to Richard and his leadership team opening a new phase in the club's evolution, with ambitious plans for investment in Old Trafford, the strengthening of our engagement with fans, and continued drive towards our most important objective – winning on the pitch."
Woodward's replacement Arnold - formerly the club's Group Managing Director - added: "I am honoured to have the chance to serve this great club and its fans. I am determined to return that honour in any way I can."
Woodward prepares to leave Man United with the club seventh in the Premier League table - four points adrift of Arsenal in the final Champions League spot with a game in hand. body check tags ::