WASHINGTON—In response to the economic fallout of the coronavirus pandemic, Congress has approved an economic-relief plan that includes one-time direct payments to most households. Here are the key details:

Payments started arriving in bank accounts the week of April 13, and a second wave of payments is coming the week of April 27. The government will be able to move fastest for people who have filed 2019 tax returns with direct-deposit information and significantly slower for those who will need paper checks.

Is there a way to give the IRS my bank account information to speed up my payment?

The IRS has now added the “Get My Payment” feature on its website that will let people check the status of their payments and provide updated bank information to get direct deposits instead of paper checks.

That can accelerate the payment by weeks or months because the government can only print about five million checks a week.

What if I’ve been having problems with Get My Payment?

The IRS on April 26 said it made several improvements to the system. That includes fixing a problem where people couldn’t enter the system if they didn’t receive a refund or owe taxes with their most recent return. Now, those people can input zero. People who had their refunds applied to estimated taxes can enter the total refund from line 21a of the 2019 return or line 20a of the 2018 return.

How soon after deposit information is entered will payments come?

Anyone who enters information before noon on a Tuesday should see their status update by the following Saturday. The payment would then likely come within a few days after that.

How much money is it?

The plan provides $1,200 for each adult and $500 for each child under 17. A married couple with two children would get $3,400. Most people will receive the money in a payment from the Internal Revenue Service soon.

Who qualifies for the stimulus payments?

The payments go to almost any adult with a Social Security number, as long as they aren’t dependents of someone else. Those adults get the payments for the children in their household. Payments start phasing out for those with income above $75,000 in adjusted gross income for individuals, $112,500 for heads of household (often single parents) and $150,000 for married couples. The payments start shrinking above those levels.

For those with no children, the benefit disappears at $99,000 for individuals and $198,000 for married couples.

Related Video President Trump signed an historic $2 trillion bill into law in late March aimed at relieving workers and businesses hurt by the novel coronavirus pandemic. WSJ breaks down what is in the package. Photo: G. Ronald Lopez/Zuma Press

How can I get the stimulus payment if I don’t usually file tax returns?

The IRS and tax-preparation companies have created a new simple form for people who have no income or too little income to file a tax return in most years. That form is now available through www.irs.gov/coronavirus and individuals can register by answering a few basic questions so the IRS knows where to find them and can send them money.

How does the IRS determine whether you are getting a payment and how much you get?

The government will use 2019 tax returns to set the payment amounts and 2018 tax returns if 2019 isn’t available.

People who haven’t filed tax returns can still file for 2019 to make sure the government has their updated income and bank-account information, as well as 2019 information about recent births, deaths, marriages, divorces and moves. Such changes that happened after 2019 won’t be reflected in the payments, however.

The IRS also will be able to get information from the Social Security Administration about people who get benefits but don’t typically file tax returns, including those who receive Social Security disability benefits.

If I am a Social Security recipient who doesn’t file tax returns, how and when will the payment come?

The payments will be made in the same way that those people currently get their Social Security benefits. Those payments should arrive by April 29, according to the Treasury Department.

For people with incomes over the limits, how does the payment work?

Those households should calculate the total amount of the credit, then subtract $5 from that total for every $100 that their adjusted gross income is over the limit. For a married couple with two children earning $180,000, the credit is reduced by 5% of the amount over the $150,000. That is a $1,500 reduction from $3,400, so their payment should be $1,900.

What about people who receive veterans benefits or Supplemental Security Income but not Social Security?

SSI recipients will get the payments automatically by early May in the same way they get their usual benefits, according to the Treasury Department. Those with dependent children who didn’t provide information to the IRS about the children by May 5 will have to wait until they file 2020 tax returns to claim those amounts. The payments won’t affect SSI eligibility. Veterans and their beneficiaries who receive benefit payments will receive the stimulus payments automatically without additional paperwork. They also had a May 5 deadline to add children.

What if I lose a substantial amount of income this year as opposed to 2019?

The advance payments will be determined based on 2019 income—or 2018 income if that is all that is available to IRS—and the final amount of the benefits will be determined based on 2020 income and settled on the 2020 tax return.

So people who ultimately qualify for more money than they receive this year—a person whose income drops from $100,000 to $70,000, for example—would get the rest through a larger tax refund or smaller tax payment in early 2021.

But people who ultimately qualify for less money than they got this year—a person whose income rises from $70,000 to $100,000—wouldn’t have to pay it back.

Besides those who make above the income threshold for the payments, is there anyone who doesn’t get a payment?

You must have a Social Security number to get a payment. Also, if you are a dependent on someone else’s tax return and you aren’t a child, you don’t get a payment.

This includes some high-school students, college students and some disabled and elderly people, many of whom show up on the tax returns of the people they live with and who provide most of their support. Immigrants who don’t have Social Security numbers also aren’t eligible and the IRS says that incarcerated prisoners aren’t eligible.

Are the payments taxable income?

No. They won’t be considered as income.

What about people who owe money to the IRS for prior years?

Other IRS liabilities won’t come out of the payments and even people who owe back taxes should get the full amount they qualify for.

SHARE YOUR THOUGHTS Do the parameters for who gets a stimulus check seem fair to you? Why or why not? Join the conversation below. If you have more questions about the economic relief plan or direct payments, fill out the form at the end of this article, and we will answer some of them in the next update.

What about child support?

The normal IRS rules for back child support and tax refunds will apply, which means that refunds for people who are behind on those payments may be smaller.

Do children born in 2020 get the payment?

Parents of children born this year won’t get a payment for that child now.

However, assuming they qualify based on their 2020 income, they would get $500 added to their tax refund or subtracted from their income-tax bill when they file their 2020 tax returns in early 2021.

What if a household didn’t get the stimulus payment or the wrong amount came?

The IRS will mail a letter 15 days after the payment has been sent. That letter should include instructions on what to do if the payment didn’t arrive.

If the payment is lower than the right amount, the IRS says the remainder can be claimed on the 2020 tax return.

What if I received a stimulus payment for a deceased family member?

Some payments have been made to people who have died. The IRS says that anyone who died before receiving the payment isn’t eligible and the people who received payments on their behalf should return them, though the agency hasn’t announced any enforcement actions in those situations to take back the payments. The IRS website now has instructions about how people can make repayments.

What happens in cases where divorced parents alternate years in which they claim a child?

The IRS said on May 11 that both parents can’t get a $500 payment now for the same child. However, the parent who doesn’t get a payment now may be able to claim up to $500 on the 2020 tax return, as long as they satisfy the rules for claiming a child during 2020.

WSJ Newsletter Get a coronavirus briefing each weekday morning, plus a curated health newsletter on Sundays: Sign up here.

Write to Richard Rubin at richard.rubin@wsj.com