If you do not owe or will get a refund you have three years to file the return without penalty. You do not really even need an extension unless you will owe. But if you want one anyway, you can request an extension online.
EXTENSION
https://turbotax.intuit.com/irs-tax-extensions/
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-extension/need-file-extension-personal-state-taxes/L32Mt8ZNv_US_en_US?uid=m9a3q808