All companies and individuals paid through Accounts Payable are required to submit a completed federal Form W-9 regardless of the amount that is being paid or the tax treatment of the payment.  If you are paying a person or company for the first time, you should request that they fill out a Vendor form. This form can be can be sent electronically, by fax, mail or in person. It is not recommended that Form W-9 with social security numbers be submitted via email.