What Business Document Do I Need? A Checklist by Situation

Every link below goes to the actual, current IRS About-Form page for that document — not a search result, not a third-party summary. For the full reference table across every form mentioned here, see our IRS Forms & Resources tool.

1. Starting a new business

The first real document almost every new business needs is an Employer Identification Number, applied for with Form SS-4 (Application for Employer Identification Number (EIN)). You need an EIN before you can open a business bank account, hire anyone, or file most business returns — even a single-member LLC with no employees generally needs one for banking purposes, even though it isn't strictly required for tax filing at that stage.

2. Choosing or changing your entity

If you're electing S-corp status for an existing LLC or corporation, that's Form 2553 (Election by a Small Business Corporation) — and it has a real deadline: generally within two months and 15 days of the start of the tax year you want the election to apply to, or at any time during the prior tax year. File it late and the election can be denied for that year entirely.

If you're changing how an eligible entity is classified for federal tax purposes more broadly — for example an LLC choosing to be taxed as a corporation instead of its default classification — that's Form 8832 (Entity Classification Election) instead. Most LLC owners only ever need the S-corp election, not this broader reclassification, but the two get confused often enough that it's worth knowing which one actually applies to your situation. See our entity structuring service if you're not sure which one you need.

3. Hiring your first employee

Every new employee fills out Form W-4 (Employee's Withholding Certificate) so you withhold the correct amount of federal income tax from their pay. This is separate from Form I-9, Employment Eligibility Verification — a required document, but a Department of Homeland Security form, not an IRS one, so it isn't covered here. If you don't already have an EIN, this is the point where you can no longer put it off.

4. Hiring a contractor

Collect Form W-9 (Request for Taxpayer Identification Number and Certification) from any contractor or vendor before you pay them, not after — it's how you get the taxpayer ID you'll need to file a 1099 correctly at year-end, and chasing it down in January from someone who's no longer answering emails is a common, avoidable problem. If you paid that contractor $600 or more for services during the year, you'll file Form 1099-NEC (Nonemployee Compensation) to report it. Rents and certain other payments that don't belong on a 1099-NEC — relevant for property owners paying rent-related amounts — go on Form 1099-MISC (Miscellaneous Information) instead.

5. Paying quarterly estimated taxes

Form 1040-ES (Estimated Tax for Individuals) is the actual worksheet and payment voucher used to calculate and pay quarterly estimated tax. If you're self-employed, self-employment tax itself is calculated on Form Schedule SE (Self-Employment Tax (Form 1040)), which feeds into the total. Our free quarterly tax calculator estimates the number before you fill out the voucher.

6. Running payroll

Once you have employees, Form 941 (Employer's Quarterly Federal Tax Return) reports income tax, Social Security, and Medicare tax withheld from paychecks each quarter. Separately, Form 940 (Employer's Annual Federal Unemployment (FUTA) Tax Return) is the annual federal unemployment (FUTA) return — a different tax, a different form, and an annual rather than quarterly filing, which is exactly why it's easy to forget the first year you have employees.

7. Buying equipment or a vehicle

Section 179 and bonus depreciation elections for equipment and vehicle purchases get claimed on Form 4562 (Depreciation and Amortization). This is the form that actually turns a large purchase into a large first-year deduction, rather than a deduction spread thin over several years — but the election has to be made correctly on this form to take effect.

8. Filing your business return

Which return you file depends entirely on your entity. A sole proprietor or single-member LLC reports business income and expenses on Form Schedule C (Profit or Loss from Business (Sole Proprietorship)), attached to their personal return. A partnership or multi-member LLC taxed as a partnership files Form 1065 (U.S. Return of Partnership Income). Once an S-corp election is in place, the business files Form 1120-S (U.S. Income Tax Return for an S Corporation) instead. Whichever one applies, the return is signed for electronic filing with Form 8879 (IRS e-file Signature Authorization).

9. Setting up a retirement plan

A business retirement plan — a 401(k), profit sharing, or cash balance plan — doesn't just require setting up the plan itself; once it's above certain size thresholds, it requires an annual Form 5500 (Annual Return/Report of Employee Benefit Plan) filing to stay compliant. This is one of the most commonly missed ongoing obligations once a plan is in place, since it's easy to treat plan setup as a one-time event rather than an annually recurring one.

10. Closing or changing your business

If you're dissolving or liquidating a corporation — including an S-corp — Form 966 (Corporate Dissolution or Liquidation) is filed within 30 days of adopting the resolution to do so. This is a step that's easy to miss entirely in the middle of winding down a business, since it's a filing requirement separate from your final tax return.

None of this replaces an actual review of your specific situation — entity type, state, and industry all change which of these apply and when. If you'd rather walk through your situation directly than match it against a checklist, a first conversation is free.