The Internal Revenue Service is ready to accept your federal tax returns starting Monday, Jan. 28.

You can file for free electronically through the IRS website or download paper forms. Tax preparation companies such as TurboTax and H&R Block are also filing tax returns to the IRS on behalf of their customers beginning Monday.

The agency recalled all its employees after the government reopened on Friday. It said in a statement Monday that it's "working to promptly resume normal operations."

The IRS expects 150 million individual returns to be filed this year, with the first refunds to go out in the first week of February. In general, the agency expects most refunds to be issued in less than 21 days. You can check the status of your refund by going to the agency's "Where's my refund?" tool online or by mobile app.

Tax help

This tax-filing season marks the first since the new tax law that passed in December 2017. The most significant changes are the increased standard deduction, the doubling of the child tax credit and the $10,000 cap on the state and local tax deduction.

The IRS expects heavy phone traffic in the the early weeks of tax season, so it encourages you to use its website to find answers before calling. Check out Publication 5307: Tax Reform: Basics for Individuals and Families.

Low- and moderate-income taxpayers can get free help with filing their tax returns at the more than 12,000 community-based tax help sites. To find one, use the site locator.

Other key tax dates

You have until Monday, April 15, to file your 2018 taxes. Taxpayers in Maine and Massachusetts have until April 17 to file their returns because of local holidays.

Here are other important tax dates:

January 31, 2019: Deadline for employers to mail out W-2 forms and for businesses to send certain 1099-MISC statements.

March 15, 2019: Tax returns for LLCs and S-corporations are due.

April 15, 2019: This is the last day you can file your taxes electronically or postmark your paper taxes.

Get ready

Collect documents: Print out a tax checklist from the IRS, TurboTax or H&R Block. Collect and file necessary tax documents like your W-2s from your employers and 1099s from your bank. Gather receipts as proof of charitable contributions, if needed.

Take out old returns: Use last year’s tax return to help you remember what credits and deductions you claimed. This can help you identify key life events that could affect your taxes, such as marriage, divorce, a home purchase, a new baby or retirement.

Anticipate changes: Use TurboTax’s TaxCaster or H&R Block’s free income tax calculator to estimate your tax situation post-tax reform law. If you need to lower your 2018 taxable income, you can fund an IRA until April 15.

This article originally appeared on USA TODAY: Taxes 2019: When does income tax season start?