The new forum and webchat was formally launched on Tuesday but has been pilot tested since March. It already has 1,000 registered users.
It aims to help people and businesses with starting a business, growing their business, buying and selling abroad, completing tax returns and tax credits.
HMRC’s webchat is linked to the forum and offers direct support to businesses and the self-employed.
However, the forum does not deal with questions about taxpayers’ individual circumstances.
The Revenue warned that any comments which include personal information will be deleted.
Instead, customers may be offered help through HMRC’s webchat service and their personal case handled by an adviser.
Mel Stride, financial secretary to the Treasury and paymaster general, said, “The UK’s 5.4 million small businesses play a vital role in our economy. We want to help businesses get off the ground and support them as they grow.
“That is why we are launching a new forum and webchat service which will give these companies useful hints and tips – including how to complete tax returns, grow a business and trade outside the UK – so that they can continue to flourish.”
Mike Cherry, FSB national chairman, said, “Having worked with us to make the rollout of Making Tax Digital more manageable for the smallest firms, it’s encouraging to see HMRC launch this new support service.
“The average small business spends over three hours a month and £3,600 a year complying with their tax obligations and administrative tasks. We hope that the Small Business Online Forum goes some way to helping firms spend less time on admin and more time achieving their commercial goals.”