ITG FAQ #1 Answer-Where do I make employment tax deposits?
Deposits of income tax withheld, and both the employer and employee portions of social security and Medicare taxes, should be made by mailing or delivering a check, money order, or cash to a financial institution that is an authorized depositary for federal taxes. Some taxpayers are required to deposit using the Electronic Federal Tax Deposit System (EFTPS). See " How do I make deposits?"
Make sure you identify the correct tax period and return (Form 941, 945, etc.) when making your deposits. It is important to make separate deposits for each type of return you are filing. Do not, for instance, combine deposits for your Form 941, Employer's Return Quarterly Federal Tax Return, with deposits for Form 945, Annual Return of Withheld Federal Income Tax. Combining deposits will result in an incorrect posting to your account and could result in additional interest and penalties.