The SS-4 is the one-page IRS form which is filed in order to obtain an Employer Identification Number (EIN). Typically, this will be filled out and submitted to the IRS immediately after incorporation. However, an entity can submit this form later in its life. It is a fairly simple form to complete. It asks for information that is usually readily available, such as the address of the headquarters, the formation date, the type of entity, etc.
You can obtain this form on the IRS website. However, many customers prefer to have IncNow assist with the process of obtaining an EIN.
MORE: How to Get an EIN