If you plan to claim a credit for child or dependent care expenses, or if you receive benefits under your employer's dependent care plan, you need to have a record of the care provider's name, address and taxpayer identification number (Social Security number or employer ID number) in order to complete Form 2441. Form W-10 is one way to get the necessary information. Others include a photocopy of the care provider's Social Security card, a recent letterhead or invoice of the care provider, or your employer's statement under its dependent care plan.
If the care provider is a tax-exempt organization you do not need its taxpayer ID number. The care provider may simply fill in "tax-exempt" in the space for the number.
When the form is complete, do not file it with your return or send it to the IRS. Just keep it with your tax records so that you can produce it if the IRS ever questions your dependent care tax benefits in the future.