Windows Desktop Invoicing Software

I need a standalone Windows desktop application that lets me create and manage invoices, store a searchable client database, and track incoming payments from issue to settlement—all in one place and without relying on a web browser. The program should install cleanly on modern Windows machines, load quickly, and keep all data safely on the local drive (a lightweight file-based database such as SQLite is fine, but I am open to your suggestion).

I want an intuitive interface where I can:
• add or edit client records and immediately pull them into a new invoice
• generate invoices with automatic numbering and basic tax or discount fields
• mark invoices as paid or partially paid and view real-time outstanding balances

Please deliver:
• a compiled 64-bit Windows installer (.exe or .msi)
• complete, well-commented source code
• brief setup/build instructions so I can recompile if needed in the future

I’m comfortable with C#/.NET (WPF or WinForms) or similar desktop frameworks; feel free to recommend another Windows-friendly stack if it achieves the same smooth user experience.

For acceptance, I will install the application on a fresh Windows machine and verify that invoice creation, client lookup, and payment status updates work exactly as described above without errors or external dependencies.