With Efile there is no W-3 form. That form is used only if you had paper filed instead. With Efile the system calculates the transmittal data and includes it in the Efile transmission.
You can run a Totals Report on the site in order to receive the same information a W-3 Form would include. To run a Totals Report after you have submitted your forms, click Order History in the top navigation and then click Totals Report sub tab. You can then run the report by invoice or payer. Select your option and click Generate Report.