You can use TurboTax Easy Extension from inside your return by following this steps -
- Log into your account
- Hit Take Me to My Return
- Underneath Manage My Return, you should see a link to File an Extension
- Click that link
- Begin your extension
You can also access from Federal Taxes > Other Tax Situations > Scroll down to Other Tax Forms > Select File an Extension
You can also use this link below -
https://turbotax.intuit.com/irs-tax-extensions/