With efile extension with that can I also apply for installments via TurboTax?

Please read the TurboTax FAQ for more information on "Can I file a Form 9465 (Installment Agreement Request) in TurboTax?": Can I file a Form 9465 (Installment Agreement Request) in TurboTax?

If you already filed, or you're unable to find this option in TurboTax, you can apply for a payment plan at the IRS Payment Plans and Installment Agreements web page (make sure you've filed your return before applying through their site).

during File an Extension option selected from Tax Tools i only see following option at the end of page. No where able to find about installment plan?

 How would you like to pay?

Direct from checking account
Direct from savings account
Mail a check or money order