Core Viewpoint - The article emphasizes the importance of declaring unbilled income for small-scale taxpayers in accordance with their quarterly sales figures, highlighting the specific reporting requirements based on different sales thresholds. Group 1: Reporting Requirements for Unbilled Income - Small-scale taxpayers must report unbilled income based on their quarterly sales. If the quarterly sales do not exceed 300,000 yuan and monthly sales do not exceed 100,000 yuan, the income can be directly filled in the "Exempt Sales Amount for Small Micro Enterprises" section of the VAT declaration form [2][11]. - If the quarterly sales exceed 300,000 yuan and monthly sales exceed 100,000 yuan, the unbilled income must be reported in the "Taxable Sales Amount (3% or 5% tax rate)" sections of the VAT declaration form [3][16]. Group 2: Additional Reporting Considerations - Taxpayers with other exempt income must also fill in the "Other Exempt Sales Amount" section and the corresponding details in the VAT exemption declaration form [5]. - If a taxpayer later issues an invoice for previously unbilled income, they must adjust the unbilled income in the month the invoice is issued, potentially leading to a negative entry in the declaration form [17].