Please see this link to guide you as prepare your W-7 form. You will need to follow the W-7 instructions for guidance on what documents to include when you mail your tax return along with your Form W-7's for all of your family members. As far as having an accountant sign the verification form, you will need to reach out to a local professional for assistance. This is not a part of the services provided by TurboTax.
How do I get an Individual Taxpayer Identification Number (ITIN)?