What kind of records should I keep? “For when the tax man cometh!”
You may choose any recordkeeping system suited to your business that clearly shows your income and expenses. The business you are in affects the type of records you need to keep for federal tax purposes. Your recordkeeping system should include a summary of your business transactions. This summary is ordinarily made in your business books (for example, accounting journals and ledgers). Your books must show your gross income, as well as your deductions and credits. For most small businesses, the business checking account is the main source for entries in the business books.
Some businesses choose to use electronic accounting software programs or some other type of electronic system to capture and organize their records. The electronic accounting software program or electronic system you choose should meet the same basic recordkeeping principles mentioned above. All requirements that apply to hard copy books and records also apply to electronic records. For more detailed information refer to Publication 583, Starting a Business and Keeping Records.
Supporting Business Documents
Purchases, sales, payroll, and other transactions you have in your business will generate supporting documents. Supporting documents include sales slips, paid bills, invoices, receipts, deposit slips, and canceled checks. These documents contain the information you need to record in your books. It is important to keep these documents because they support the entries in your books and on your tax return. You should keep them in an orderly fashion and in a safe place. For instance, organize them by year and type of income or expense.
Click here for more information:
https://www.irs.gov/businesses/small-businesses-self-employed/what-kind-of-records-should-i-keep