I have filed an easy extension but didn't pay the tax. Now I need to pay the estimated tax before tomorrow. Can you help me find that form?

The form is 4868 which can be printed in TurboTax. Here is the form and instructions from the IRS:

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

when you request an extension you're expected to pay the full balance.
go to www.irs.gov/payments and "Make a payment"
select Reason: Extension

Make a note of your payment  amount so you can claim credit for that when you file.