If you haven’t filed your taxes yet, you still have options. First, you can electronically prepare and file your tax return. In most cases, you can do so for free by going to IRS.gov and clicking on the blue and green Free File icon.
“If you owe taxes, you can e-file now and pay later by setting your payment date for April 17,” said Clay Sanford, an IRS spokesman in Dallas. “If you’re going to need additional time, you can request an extension as long as you do it by April 17—this can also be accomplished with Free File.”
If you’re filing for an extension by paper, use IRS Form 4868 which you can download from IRS.gov.  Remember, an extension of time to file is not an extension of time to pay.
If you owe money, make your best estimate and pay that when you send your extension request.  If you can’t pay it all right now, file anyway. The failure-to-file penalty is generally more than the failure-to-pay penalty. So, if you cannot pay all the taxes you owe, you should still file your tax return on time and explore other payment options in the meantime. The IRS will work with you.  For more information, see1040 Central at irs.gov.