You can apply for extension to file tax return by filing the Form 4868 electronically or you can fill out the form and mailing it to the place where you will file your return. Other option is by paying part of your tax by credit card. An extension of time to file tax return is NOT an extension of time to pay, which should be paid by April 15th to avoid interest and penalties.
Forms to Use:
Form 4868
References:
Check other state tax links below.