Form 7004 is the extension form for businesses and not for individuals. The extension form for individuals is Form 4868.
Currently the Form 4868 is not currently available to file electronically. It will become available later in the tax season. If you need to file an extension now, you can print the form and mail it into the IRS.
When using the TurboTax Business software, the Form 7004 is available to electronically file.
To access the business software see Business Software.