After filing a tax extension, taxpayers should prepare and file their tax return as soon as possible by the new October 15 deadline to avoid penalties. They may need to hire a tax professional to prepare their return if they have a complicated financial situation. While an extension provides more time to file, it does not extend the deadline to pay taxes owed, so taxpayers should pay an estimate of taxes due by April 15 to avoid failure to pay penalties. If unable to pay, taxpayers can set up a payment plan with the IRS or a tax professional.