Direct File marks the widespread debut of a free, government-run answer to mass-market online tax preparation from commercial providers like TurboTax and H&R Block The Internal Revenue Service’s free tax-prep platform will soon be open for business.

After slowly increasing capacity on its Direct File platform, the IRS will make the platform available to a wider audience on Monday, the agency said.

The platform is expected to be fully up and running on March 12. The pilot program can only prepare relatively basic tax returns, and it will only be available to eligible taxpayers in 12 states: Arizona, California, Florida, Massachusetts, Nevada, New Hampshire, New York, South Dakota, Tennessee, Texas, Washington state and Wyoming.

But Direct File marks the widespread debut of a free, government-run answer to mass-market online tax preparation from commercial providers like TurboTax INTU, +0.55% and H&R Block HRB, -1.65%.

Regulators at the Federal Trade Commission have alleged that both TurboTax and H&R Block misled consumers about the extent of their free tax-preparation services. Both companies deny the allegations.

There are other free tax-filing options out there, including the IRS Free File program. That’s an IRS partnership with tax-software companies available to taxpayers with incomes of up to $79,000.

The IRS Direct File program has no income limits, just like the free tax-prep programs from H&R Block HRB, -1.65% and TurboTax INTU, +0.55%. But all three can only be used for certain types of tax returns, mostly simple ones.

The IRS has slowly rolled out Direct File, making it available to taxpayers for certain hours of the day. Starting March 4, it will be available to new users 24 hours a day every day, according to an IRS official.

However, people who want to use the platform should look for a notice at the top of the site saying it’s open. The platform may be temporarily unavailable at times if too many users take up all the available slots for a given day, the official said.

“But more spaces will be added every day, and our goal is to ensure that all taxpayers who are interested and eligible can try out Direct File for themselves,” the IRS official added.