Which document identifies the tax obligations due to the IRS for an employee?

The W-2 form is the document that identifies the tax obligations due to the IRS for an employee. Specifically, it provides a summary of an employee's earnings and the taxes withheld from their paycheck during the year, including federal income tax, Social Security tax, and Medicare tax. Employers are required to file W-2 forms with the IRS and provide copies to their employees by the end of January each year. This allows the IRS to track income and tax obligations accurately, ensuring that individuals report their income correctly on their tax returns.

In contrast, the W-4 form is used by employees to inform their employer of their withholding preferences for federal income tax purposes. It does not directly indicate tax obligations but rather helps determine how much tax should be withheld from an employee's paycheck. The 1099 form is primarily used for reporting income received from sources other than an employer, such as freelance work or other non-employee compensation, and is generally associated with independent contractors rather than employees. The W-10 form is used for reporting the names and social security numbers of individuals providing dependent care services, which is not related to employee tax obligations. Thus, the W-2 stands out as the correct choice for identifying tax obligations owed to the IRS by employees.