Document category
Taxpayer identity, withholding and ID application forms
Choose among W-9, W-4, W-7 and SS-4 by the identification, election or application task you need to complete.
W-9 supplies taxpayer information to a requester, W-4 supplies employee withholding elections, W-7 applies for an ITIN and SS-4 applies for an EIN. A prepared application does not issue an identification number.
Choose the document by its recipient
A client requesting taxpayer information generally has a different task from an employer collecting withholding elections. An IRS identification application has another submission process and supporting requirements. Confirm who asked for the document and what it is meant to accomplish before entering identifiers.
Names and numbers need to belong together
Use actual legal names and the identifier appropriate to the taxpayer or entity. Business and trade names are not always interchangeable. The editor checks supported formats; it does not verify that a number belongs to a person or entity.
Review certification and delivery
Check signatures and application attachments in the official instructions. Use a secure delivery channel for taxpayer numbers. Formz prepares the supported PDF; a requester handoff, IRS application submission and approval are separate events.
Official sources
Source links reviewed October 4, 2026. Use the instructions for your selected year and check current agency updates before submission.