Which document is commonly used for salary withholding in payroll?

The document commonly used for salary withholding in payroll is Form W-4. This form is completed by employees and provides their employer with necessary information regarding their withholding allowances and personal tax situation. The information on the W-4 helps the employer determine the correct amount of federal income tax to withhold from the employee's paycheck, ensuring that the employee's tax liability is minimized when they file their annual tax return.

Form W-9 is used to request a taxpayer identification number and certification for individuals and businesses, which is not directly related to withholding salary. Form 941 is a quarterly report filed by employers to report income taxes, Social Security tax, and Medicare tax withheld from employee wages, but it does not provide the initial withholding information needed for each employee's paycheck. Form 1099 is used to report various types of income other than wages, salaries, and tips, and it also doesn't pertain to salary withholding in payroll.