The IRS extended the filing deadline to May 17, 2021. This doesn’t extend your state filing deadline. Only a handful of states have extended their filing deadlines. Kansas is the latest state, as of yesterday, to extend the state filing deadline as May 17, 2021. The extension does not apply to estimated tax payments.
If you live in a state that requires filing a state tax return, check your state’s filing date. Same if your city or county requires you to file tax returns.