When you keep tax receipts and documents for six years, it could become challenging to look back at an expense and remember what it was for. This is where annotating your receipts comes in handy. Annotating receipts means that you write notes and details on the receipt to help explain the expense. The information you should include is what the expense is and how the payment relates to your income tax return. It’s best to make these notes right after the purchase, so you’re not struggling to remember details later.