Tax filing season kicks off. Here's what to know.

Tax filing season kicked off on Monday as the U.S. Internal Revenue Service began accepting completed tax forms.

Americans can file anytime before April 15. The IRS said earlier this month that it expects more than 140 million individual tax returns to be filed by that deadline.

Refunds are typically sent within 21 days, the agency says. For paper returns, the IRS says turnaround time can last more than four weeks.

The IRS is expanding a system that allows taxpayers to file directly with the agency, bypassing intermediary firms that often charge fees.

The initiative, Direct File, will be made available to taxpayers in 25 states, more than doubling from 12 states last year, the IRS said.

States newly offering Direct File include Alaska, Connecticut, Idaho, Illinois, Kansas, Maine, Maryland, New Jersey, New Mexico, North Carolina, Oregon, Pennsylvania and Wisconsin.

For the first time, the Direct File program will feature a “data-import tool” that allows tax filers to automatically enter information available in their IRS account, the agency said. Direct File works on mobile phones, laptops, tablets or desktop computers, the IRS said.

Up to one in three Americans waits until the last minute to file their taxes, according to a 2021 survey by IPX 1031. That amounts to tens of millions of people.

Taxpayers can typically file an extension that lasts six months, meaning those who obtain an extension will be allowed to submit their tax forms without penalty until Oct. 15.

If a filer forgoes an extension and files late, the person risks additional fees for the tardy submission. The penalty amounts to 5% of the taxes owed for each month that the filing is late, up to a maximum of 25%.

Under such circumstances, the IRS mails a letter or notice alerting the filer of a late fee.