Louis van Gaal has already spent upwards of £50m on Luke Shaw and Ander Herrera, but the new United boss looks set to add more faces before the season begins.
The Dutchman has been linked with Arturo Vidal, Daley Blind, Kevin Strootman and Thomas Vermaelen since taking charge in May.
Woodward says there is plenty of cash available to Van Gaal if he decides he needs to strengthen further.
"There is no fixed budget. Financially we are extremely strong, we have funds available," United's executive vice-chairman told MUTV in an interview filmed on the club's pre-season tour of the United States.
"Louis is the boss and is assessing what's going on but we have been in dialogue for some time about targets so there is a lot of work going on behind the scenes... we're continuing to move forward on some of those targets... so watch this space.
"The time he (Van Gaal) spends here as well (in America) he'll be able to assess more what he's got and continue to tweak the decisions if we need to.
"We want to do what it takes to win the title."
United finished seventh under David Moyes last year, meaning they will be without European football this term for the first time in almost two decades.
Woodward does not believe that will put potential signings off a move to Old Trafford though.
He added: "I've experienced a lot of conversations with agents and players and we are still a huge attraction to top football stars around the world - there is no doubt about that.
"We've already invested in two new fantastic players."As a consequence of the club's failure to qualify for Europe, United will play a vastly reduced number of matches this season.
Van Gaal will therefore need fewer players, so there is a high possibility that some squad members will be moved on before the transfer window closes.
Patrice Evra may follow Rio Ferdinand and Nemanja Vidic out of the door despite only signing a new contract two months ago.
Midfielder Anderson, who was loaned to Fiorentina last season, and misfiring striker Bebe are free to leave.
The likes of Javier Hernandez, Wilfried Zaha, Marouane Fellaini, Anderson and Tom Cleverley all have question marks over their futures.
When asked whether players would leave, Woodward said: "Yes, I think so.
"The manager makes that decision and a few players have already gone and there may well be a few others that go.
"It's also worth commenting that we're not in Europe this year (so) there's less games, maybe the manager takes the view that he wants a tighter squad to bed in.
"If you do the analysis over last year, Liverpool performed extremely well with a smaller number of players but that's a decision for the manager."
Woodward is convinced the United boss will not shy away from making any tough calls.
"We've got someone who has confidence in himself about making difficult decisions and, when you boil down what makes a great manager, one of the key characteristics is making difficult decisions and we've clearly got a manager who can do that," Woodward added.
"I've personally found him very warm. He's a very clear communicator and very direct. I like that in people; I'm a very direct person myself."
Failing to qualify for Europe was a big blow to United, who have won the Champions League on three occasions.
Woodward wants an instant return to the biggest competition in European football, but he also stressed his desire for United to challenge for the Barclays Premier League too.
"We're a club that absolutely should be in the Champions League," he said.
"That's what our fans want, that's what our players want and that's what every member of staff wants.
"We have to strive to win. We're not here to be an also-ran; we're here to win trophies to add to that huge, incredible list that we've won over many years."
Van Gaal may have been in his post for only five days, but Woodward says the 62-year-old, who led Holland to the last four of the World Cup, has already made a big impact.
"I'm hearing a lot of good feedback from a lot of people about him and there is a huge amount of goodwill towards him and the coaching staff," Woodward said.
"Every interaction he's having with people is leaving an imprint, which is superb."