More than 8 million households in England, Wales, Scotland and Northern Ireland will receive £324 this month as part of the Government's support package.
It is the second of two payments totalling £650, with an initial £326 being paid to those eligible in July.
Those who qualify to receive the money will have it paid directly into their bank accounts by the end of November. They do not need to do anything as the Department for Work and Pensions will have their details.
So people should watch out for texts and emails from scammers asking them to make applications online.
During the first wave of payments in the summer, there were reports of text messages being sent which looked like they were from the DWP, asking an individual to send their bank details to confirm where they wanted the money paid.
Citizens Advice Medway wrote: "Never provide bank details to an untrustworthy source. Official bodies such as the DWP would never request this information from you via text message."
The payment reference on DWP recipients' bank accounts will be their national insurance number, followed by "DWP COL". For HMRC recipients, the payment reference will be "HMRC COLS".
People will receive the money if they are on Universal Credit, Income-based Jobseekers Allowance (JSA), Income-related Employment and Support Allowance (ESA), Income Support and Pension Credit.
There is also help for those on certain credits.
Claimants must have been receiving and entitled to a payment of these benefits between August 26 and September 25, apart from pensioners who may be able to have a new Pension Credit claim backdated.
Pensioners have until December 18 to submit a valid claim for Pension Credit to be in receipt of the £324 cost of living payment. The Government's online calculator will show if a person is entitled to Pension Credit.
HMRC will also make the payment to those who receive Working Tax Credit or Child Tax Credit and no other benefits. Again this will be paid automatically. More than a million people are expected to receive the payment from HMRC.
Work and Pensions Secretary Mel Stride said: "We understand that people are struggling and that is why we've consistently acted to ensure millions of low-income families are supported. We will continue to act with compassion as we navigate challenging global economic circumstances.
"As part of a wider £37 billion package of support, this latest £324 payment will help the most vulnerable people in our society who are worrying about their finances through the winter months."
Other Government support
- £400 discount on energy bills - paid monthly to energy customers.
- £300 Winter Fuel Payments - for pensioners over winter.
- Household Support Fund - £421m handed to councils to give out to those in need between October and March however authorities see fit.
- £150 Disability Cost of Living Payment.