US Finance & Tax Guides
Clear, source-backed explanations of federal income tax, withholding, estimated payments and small-business bookkeeping for individuals and business owners.
Start with the guide that matches your situation. TaxNexus explains the process in plain English and links to the relevant IRS material so you can confirm current requirements before acting.
Federal Income Tax Filing
Understand Form 1040, filing preparation, common records and the difference between withholding and a final tax return.
Read the filing guide →Form W-4 & Withholding
Learn when to review withholding and how filing status, additional income, deductions and credits affect Form W-4.
Read the withholding guide →Quarterly Estimated Tax
A practical introduction to estimated payments for self-employment and income not adequately covered by withholding.
Read the estimated-tax guide →Small-Business Bookkeeping
Build a clean recordkeeping system for income, expenses, supporting documents and tax preparation.
Read the bookkeeping guide →Primary sources
IRS Individual Tax Filing · IRS Tax Withholding · IRS Recordkeeping
