It lists four priorities for a Biden-Harris administration: COVID-19, economic recovery, racial equity and climate change.
"The team being assembled will meet these challenges on Day One," it said in a reference to 20 January, 2021, when Mr Biden will be sworn in as the 46th President of the United States.
Mr Biden delivered a message of unity and conciliation in a speech in his home state of Delaware on Saturday, saying it was “time to heal” the nation.
“The work starts right away,” Mr Biden Deputy Campaign Manager Kate Bedingfield said on Sunday on NBC’s “Meet the Press.”
Ms Bedingfield said Mr Biden planned to launch a coronavirus task force on Monday, led by former Surgeon General Vivek Murthy and former Food and Drug Administration Commissioner David Kessler.
More than 237,000 Americans have died of COVID-19 and coronavirus cases have spiked to record numbers in recent days. Some 10 million Americans thrown out of work during coronavirus lockdowns remain idled and federal relief programs have expired.
Mr Biden and his advisers will also move forward with the work of choosing officials to serve in his administration.
Ms Bedingfield added that Mr Biden would “address a mandate to bring the country together - to unify, to lower the temperature, to set aside the harsh rhetoric of the campaign and get to the hard work of governing.”
The bipartisan Partnership for Public Service’s Center for Presidential Transition said Mr Biden had clearly won and called for the Trump administration to work cooperatively with him.
“History is replete with examples of presidents who emerged from such campaigns to graciously assist their successors,” it said in a statement.
Two former senior US intelligence officials - Michael Morell and Avril Haines - have emerged as leading contenders to serve as director of national intelligence or run the CIA under Mr Biden, several current and former intelligence officials said.
After attending church in Wilmington, Delaware, Mr Biden and his family visited the church’s cemetery, where his son Beau and other relatives are buried - as he did on the morning of Election Day on Tuesday.
According to an adviser, Mr Biden plans to repeal a ban on travelers from several Muslim-majority nations, rejoin an international climate accord, reverse Mr Trump’s withdrawal from the World Health Organization and buttress a program protecting from deportation “Dreamers” brought to the United States illegally as children.
Senate control still at stake
Mr Biden's advisers have told reporters that if Republicans retain control of the US Senate, he may have to appoint Cabinet officers of a more centrist bent to secure confirmation in the chamber.
Mr Biden has long kept a tight inner circle that includes family members and his chiefs of staff during his years as Barack Obama’s vice president: Ron Klain, Steve Ricchetti and Bruce Reed. Mr Biden also is turning to others including campaign adviser Anita Dunn, former US Senator Ted Kaufman of Delaware and economic adviser Jeff Zients.
Control of the Senate could depend on the outcome of four undecided Senate races, including two in Georgia that will not be resolved until January runoffs.
Wearing his trademark “Make America Great Again” baseball cap, Mr Trump golfed at his course in Sterling, Virginia, for the second day in a row. His motorcade was met by a smattering of admirers and detractors holding signs, including one that read: “Mr Trumpty Dumpty Had A Great Fall.”
Unlike other past defeated US presidential candidates, Mr Trump has not made a concession statement or reached out to Mr Biden.
“Since when does the Lamestream Media call who our next president will be?” Mr Trump wrote on Twitter after golfing.
In another tweet, he cited an ally, former Republican House speaker Newt Gingrich, as saying the "best pollster in Britain wrote this morning that this clearly was a stolen election".
In another series of tweets, Mr Trump quoted a George Washington University law professor who testified on his behalf during his impeachment in Congress.
"We should look at the votes," Jonathan Turley said in the tweets quoted by Mr Trump. "We should look at these allegations. We have a history in this country of election problems".
Mr Trump left out another part of the professor's opinion in which he stated that while there is "ample reason to conduct reviews" there is "currently no evidence of systemic fraud in the election".
Meanwhile, first lady Melania Trump tweeted about the election for the first time since Mr Biden was projected as the winner, echoing calls by her husband for only legal votes to be counted.
"The American people deserve fair elections. Every legal - not illegal - vote should be counted. We must protect our democracy with complete transparency," she said.
The Trump campaign has mounted legal challenges to the results in several states but no evidence has emerged so far of any widespread irregularities that would overturn the results of the election.
Speaking on CNN's "State of the Union" on Sunday, Symone Sanders, a senior advisor to Mr Biden, dismissed the court challenges as "baseless legal strategies."
'A more graceful departure'
Mr Biden received nearly 74.6 million votes to Mr Trump's 70.4 million nationwide, and has a 279-214 lead in the Electoral College that determines the presidency.
Mr Biden also leads in Arizona, which has 11 electoral votes, and Georgia, which has 16, and if he wins both states he would finish with 306 electoral votes - the same total won by Mr Trump in 2016 when he upset Hillary Clinton.
Former President George W Bush - a Republican - congratulated Mr Biden on his election win on Monday, saying the American people could have confidence the election was "fundamentally fair" and "its integrity will be upheld".
Only two Republicans senators - Mitt Romney and Lisa Murkowski - have congratulated Mr Biden on his victory and Democratic Representative James Clyburn of South Carolina said the Republican Party has a "responsibility" to help convince Mr Trump that it is time to concede.
"What matters to me is whether or not the Republican Party will step up and help us preserve the integrity of this democracy," Mr Clyburn said on CNN's "State of the Union."
Mr Romney, who voted to convict Mr Trump at his impeachment trial, said the president has "has every right to call for recounts" but he should be careful with his "choice of words."
"I'm convinced that once all remedies have been exhausted, if those are exhausted in a way that's not favorable to him, he will accept the inevitable," Mr Romney said.
The Utah senator added that he "would prefer to see the world watching a more graceful departure, but that's just not in the nature of the man."
Speaking on ABC's "This Week," another Republican senator, Roy Blunt of Missouri said "it's time for the president's lawyers to present the facts and it's time for those facts to speak for themselves."
Former Republican governor and Mr Trump's friend, Chris Christie, said the president had to back up his claims that the election was stolen.
"If your basis for not conceding is that there was voter fraud, then show us," Mr Christie told the same program. "We can't back you blindly without evidence."
Mr Christie said Mr Trump had been a friend of his for 20 years, "but friendship doesn't mean that you're blind".
However, Trump ally Senator Lindsey Graham of South Carolina said the president should keep fighting.
"We will work with Biden if he wins, but Trump has not lost," Mr Graham said on the Fox News show "Sunday Morning Futures." "Do not concede, Mr. President. Fight hard."
Allies of Mr Trump, House minority leader Kevin McCarthy and Texas Senator Ted Cruz, also told Fox News it was too early to call the election.
"What we need in the presidential race is to make sure every legal vote is counted, every recount is completed, and every legal challenge should be heard," Mr McCarthy said.
Mr Cruz claimed the media had tried to get everyone to "coronate" Mr Biden, but "we do not know who has prevailed in the election".