The IRS says taxpayers should gather personal information such as Social Security numbers or ITINs for everyone on the return, bank account and routing numbers for direct deposit or payment, and prior-year information such as your adjusted gross income and exact prior-year refund amount if needed. The IRS also says your name should match Social Security Administration records.

 

For income, the IRS says you should have forms and records such as W-2s, 1099s, receipts, canceled checks, and other documents that support income, deductions, or credits reported on the return. For many people, that also includes documents like 1098 forms, brokerage statements, retirement distribution forms, and records tied to education, dependents, mortgage interest, charitable giving, or health coverage, depending on what applies to the taxpayer.

 

If you have a business, the IRS says supporting documents should include items such as sales slips, paid bills, invoices, receipts, deposit slips, canceled checks, payroll records, and records of purchases, sales, and other transactions. These documents support the entries in your books and the amounts on the return.

 

So the best practical answer is that you need everything required to prove who you are, how much income you received, and every deduction or credit you plan to claim. The exact list changes with the facts of the return, but the IRS consistently frames tax prep as gathering records for income, payments, deductions, and credits before filing.