Stockholders will receive $54.20 per share as part of the deal, a 38 per cent premium over the social platform's closing stock price on April 1. The deal is expected to be completed by the end of the year.
“Free speech is the bedrock of a functioning democracy and Twitter is the digital town square where matters vital to the future of humanity are debated,” Mr Musk said in the statement.
“I also want to make Twitter better than ever by enhancing the product with new features, making the algorithms open source to increase trust, defeating the spam bots, and authenticating all humans. Twitter has tremendous potential — I look forward to working with the company and the community of users to unlock it.”
Mr Musk tweeted a screenshot of his statement with emojis of rockets, shooting stars and hearts. “Yesss!!!” he said.
Twitter shares on Monday were trading up more than 5 per cent at about $52.00.
“Twitter has a purpose and relevance that impacts the entire world. Deeply proud of our teams and inspired by the work that has never been more important,” Twitter's chief executive Parag Agrawal said in the statement.
The company had an all-hands video call on Monday to discuss the deal, during which news agencies reported Mr Agrawal said there would be no job cuts and that a hiring freeze is now in place.
Mr Musk will soon join the company's staff for a question-and-answer session, he added.
"Once the deal closes, we don't know which direction the platform will go," Mr Agrawal was quoted as saying by Bloomberg and Reuters, citing audio from the meeting and people who attended.
Last week, Mr Musk, the billionaire chief executive and co-founder of Tesla, the world’s biggest electric vehicle company, said he had a funding commitment of $46.5bn to finance his bid to buy Twitter and was considering initiating a tender offer for its shares.
Mr Musk said on Thursday in a regulatory filing that he personally committed to provide $33.5bn for the deal. This will include $21bn of equity and $12.5bn from margin loans.
Twitter’s board is believed to have met on Sunday to discuss Mr Musk’s financing plan for his proposal.
This April, Mr Musk offered to buy 100 per cent of Twitter but the company's board moved to shield itself from the takeover bid by adopting a limited-duration shareholder rights plan, which would enable its shareholders to buy additional stock under a “poison pill” strategy.
Mr Musk's offer came after frequent complaints about claims of content censorship and lack of free speech on the site.
“Given that Twitter serves as the de facto public town square, failing to adhere to free speech principles fundamentally undermines democracy. What should be done?” Mr Musk said on Twitter last month.
In response to his poll, 70.4 per cent of users said Twitter does not stick to free speech principles, while 29.6 per cent supported the platform.
He tweeted earlier on Monday as Twitter users claimed they'd leave the platform: “I hope that even my worst critics remain on Twitter, because that is what free speech means.”
In response to a reporter's question on the deal, White House Press Secretary Jen Psaki said: “President [Joe Biden] has long talked about his concerns about the power of social media platforms, including Twitter and others to spread misinformation, disinformation, the need for these platforms to be held accountable.”
Mr Musk’s deal has met resistance, particularly from Twitter’s shareholders.
Saudi billionaire Prince Alwaleed bin Talal, who owns a stake in Twitter through his Kingdom Holding Company, rejected Mr Musk’s offer last week, saying it did not “come close to the intrinsic value of Twitter given its growth prospects”.
The firm with more than $103bn in assets under management as of the end of December informed Twitter that it was exploring such a move, Reuters reported, citing sources.
However, Reuters also reported that Twitter didn't receive competing acquisition offers from other companies or firms.
"The pressure was on for Twitter to make a decision on Musk’s deal before Thursday’s earnings announcement as many were expecting disappointing results," Edward Moya, senior market analyst for the Americas at New York-based Oanda, said.
Twitter is expected to announce its first quarter earnings for the year on Thursday.
“We could perhaps see Twitter miss numbers later this week … that wouldn’t be a huge surprise given their well-documented struggles to monetise the platform,” Neil Campling, co-head of Mirabaud Securities' Global Thematic Group, told The National.
The company’s net loss for the 2021 financial year narrowed to $221.4 million compared to the $1.14bn loss it posted in 2020.
That was on the back of improved revenue, which rose 37 per cent on an annual basis to more than $5bn last year.