You are entitled to a six-month extension if you need more time to file your tax return by the April 18 deadline, but you must let the IRS know. You’ll need to complete Form 4868 before the April 18 due date. Otherwise, without telling the IRS you’ll be filing your return later, you could end up paying penalties and interest on unpaid taxes.
While you can extend the due date to file your tax return, there is no extension to extend the payment of any tax you owe. Remember that an extension is an extension to file, not an extension to pay.
Businesses can also file for an extension to file corporate tax returns using Form 7004.
Neither Form 4868 nor 7004 need to be signed, but you’ll want to include your payment for any tax due when you file your extension application.