Do I have to use my Social Security Number when I eFile my form 7004 business tax extension, or will I use my Tax-ID (EIN) number?

For most business types, you will simply need your Federal Tax ID number — also called your Employer Identification Number (EIN) — to file your business tax extension (IRS Tax Form 7004). If you are requesting an extension for a single-member LLC business, you should file for a personal tax extension (IRS Tax Form 4868) and use your Social Security Number (SSN) rather than your EIN.