Just had back surgery and I need an extension until October 15

See the following FAQ.

How do I file an extension?

An extension is an extension of time to file your tax return, not an extension of time to pay. If you owe additional tax, you have to pay by July 15 to avoid penalties and interest.

You don’t need to file Form 4868 if you make a payment of any amount using the IRS electronic payment options.

**indicate that the payment is for an extension** using Direct Pay, the Electronic Federal Tax Payment System, or using a credit or debit card. Your extension is then automatically granted and you will receive a confirmation number for your records.