Here's what to know about filing for an extension on your tax returns

An IRS backlog from the pandemic means a possible delay in getting a refund.

For those who have either procrastinated or been unable to send in their tax returns by Monday's deadline, the IRS says filing for an extension might be the best option.

The simplest way to file for an extension is to go to the IRS Extension page and use its Free File page to estimate your tax liability and pay any amount due before midnight on April 18.

Although this extension will give taxpayers until October 17, 2022 to complete their returns, they must pay taxes owed by the original due date or face penalties, according to the IRS.

Eric Smith, an agency spokesman, told ABC News if you believe you'll owe the IRS, it's better to overestimate your income to make sure you're paying your full tax amount instead of paying for any interest on a potentially remaining balance.

While overestimating your income might have you pay more taxes initially, you'll receive any refund when you complete your filing by the October extension deadline. Smith also recommended calling the IRS hotline at 800-829-1954 if you want to check on the status of your refund at any time.

For your state-specific tax questions you can visit the Federation of Tax Administrators to find your state's specific tax extension procedures.

There's a significant difference in the time it takes for Americans get their refunds based on the way they file -- either electronically or by mail.

"The IRS has encouraged electronic filing for over 30 years," Smith said, "but some don't have the option to file electronically," such as those without internet or computer access.

"With an electronic file, you get that verification when everything is completed and if rejected, you can correct it right away. With a paper filing, when there's something missing, a signature somewhere, or you forgot to attach a W-2, then we have to write back and request that. Only when we get that back, can we start to process those returns," he said.

Smith warns that when you file your taxes with paper, you could be waiting weeks, if not months, for a notice that something wasn't submitted properly and even longer to correct any filing mistakes.

Even for these individuals, families, and businesses who have filed on time, the backlog could still delay the refund many people rely on for months as the IRS tries to process current filings and alleviate their bottleneck from 2020. To address the historic pandemic backlogs, the IRS created a surge task force comprising 800 membered of experienced IRS employees that they hope to fully address the bottleneck well before the end of 2022 barring any unforeseen circumstances.

Treasury Department Deputy Secretary Wally Adeyemo points to the nearly decade-long defunding of the IRS for the severe backlogs that have plagued the taxpayer since the COVID-19 pandemic began. "Chronic underfunding by Congress has made it harder for you and other taxpayers to get answers from the IRS. But the president is calling for an increase in the budget for the IRS over time," Adeyemo said on ABC's "GMA3."

"Last year, the IRS received over 200 million calls and only had 15,000 people to answer those calls. That's about 16,000 calls per person. The IRS is short thousands of employees. We have the same number of employees at the IRS as we had in 1970. And the U.S. population is 60% greater than it was at that point. So, there are thousands of people we need at the IRS to help make sure that when you call, the phone calls can be answered," he said.

He also highlights the lack of technological modernization hindering the IRS, noting the information system it uses to process returns was built in 1962.