Here is a link on information for individuals for filing an extension.

It’s super easy.

If you think you’ll owe money, send in some money. If you don’t owe that much, you’ll get it refunded. It’s better than paying penalties.

If you think you’ll owe CA as well, here’s there extension form. I don’t have the informaiton for other states.

https://www.irs.gov/pub/irs-pdf/f4868.pdf

You only need to file the CA extension if you think owe CA money.
Otherwise it’s automatic when you file your federal extension.

If you think you owe no money, put down zeroes on the extension form
along with your name, address, and social and send it in. You don’t
even have to sign, it’s that easy.

Extensions must be postmarked by April 15. Send certified to prove
you filed it in case the IRS / Post Office looses the form. (It’s
rare, but it happens. Don’t ask me how I know)