Speaking at the daily coronavirus briefing at 10 Downing Street, Chancellor Rishi Sunak announced the support, and said many charities also benefited from schemes already announced by the Government.
But he said for those on the frontline of tackling coronavirus or supporting the vulnerable "shutting up shop at this moment would be to contravene their very purpose".
Some £370m of that will be for small charities working with vulnerable people through the National Lottery.
And £360m will go to charities providing essential services, including £200m to hospices.
Mr Sunak said: "We need the gentleness of charities in our lives. It gives us hope, it makes us stronger, and reminds us we depend on each other.”
The Government has also pledged to match the public’s donations to the National Emergencies Trust, guaranteeing a minimum of £20m.
It will match fund whatever the public decides to donate to the BBC’s Big Night In charity appeal on April 23.
Mr Sunak said: “Our charities are playing a crucial role in the national fight against coronavirus, supporting those who are most in need.
“It’s right we do everything we can to help the sector during this difficult time, which is why we have announced this unprecedented £750m package of extra funding.
“This will ensure our key charities can continue to deliver the services that millions of people up and down the country rely on.”
Tens of thousands of charities are expected to benefit, including hospices, St John’s Ambulance to help it support the NHS, vulnerable children and victims services and Citizen’s Advice, to increase the number of staff providing advice.