You should file your tax return by the deadline even if you cannot pay the full amount due.
If you owe taxes, but can't pay in full by the May 17, 2021 deadline, you should:
File your tax return or request an extension of time to file by the May 17 deadline.
If you owe tax and do not file your return on time or request an extension, you may face a failure-to-file penalty for not filing on time.
Remember that an extension of time to file is not an extension of time to pay. An extension gives you until October 15, 2021 to file your 2020 tax return, but taxes owed are still due May 17, 2021.
To get an extension to file, do one of the following:
File Form 4868 through your tax professional, tax software or using IRS Free File.
Submit an electronic payment with Direct Pay, Electronic Federal Tax Payment System or by debit, credit card or digital wallet and select Form 4868 or extension as the payment type.
Pay as much as possible by the May 17 due date.
Whether filing a return or requesting an extension, you must pay your tax bill in full by the May deadline to avoid interest and penalties.
If you don't pay your taxes on time, you will face a failure-to-pay penalty.
The IRS has options for if you can't afford to pay taxes you owe.
Set up a payment plan as soon as possible.
If you owe but cannot pay in full by May 17 you don't have to wait for a tax bill to set up a payment plan.
You can apply for a payment plan on the IRS website.
You can also submit a payment plan request using Form 9465, Installment Agreement Request.
Resources: IRS extends additional tax deadlines to May 17
What Is the Due Date of My Federal Tax Return or Am I Eligible to Request an Extension?
Tax Topic 653, IRS Notices and Bills, Penalties, and Interest Charges