| Invoice Number | Unique sequential identifier. Format: INV-YYYY-NNNN | Yes, on Issue |
| Client | Linked CRM client record with all billing details | Selected by user |
| Issue Date | Date the invoice was officially issued | Yes (today) |
| Due Date | Payment deadline based on client's payment terms | Yes (from client terms) |
| Line Items | Services rendered with qty, unit price, and taxes | From shipments or manual |
| Subtotal | Sum of all line items before taxes and discounts | Calculated |
| Discounts | Any negotiated discounts applied (% or fixed) | Manual or from contract |
| Taxes | Tax amounts per configured tax rate | Calculated |
| Total | Final amount due after all adjustments | Calculated |
| Notes | Free-text notes printed on the invoice PDF | Optional |
| Internal Notes | Notes for internal use only — not shown on PDF | Optional |
