Windows Desktop Accounting Software

I need a full-featured Windows desktop application that handles day-to-day accounting for small businesses. The core feature-set is clear:

• Invoicing & billing – create, send, print, and track customer invoices with tax and discount support.
• Expense tracking – quick entry screens, category management, receipt attachment, and searchable history.
• Financial reporting – P&L, balance sheet, cash-flow, and customizable date-range summaries exportable to PDF / Excel.

The program should install cleanly on modern Windows 10/11 machines without extra dependencies for the user. A responsive, modern UI (WPF, WinUI, Qt, or similar) is welcome as long as it remains fast and intuitive. I will also need:

• Reliable local data storage (SQLite, LiteDB, or another embedded solution) with secure backup / restore.
• Role-based access so multiple staff members can log in with appropriate permissions.
• Source code, build instructions, and concise user documentation handed over at the end of the project.

I’m flexible on the tech stack—C#/.NET, C++/Qt, or another robust option that you are comfortable supporting long term. Clean architecture, clear separation of concerns, and well-commented code matter more to me than the specific framework.

Acceptance criteria: the three core modules work end-to-end; reports match sample data I will supply; the installer runs without errors on a fresh Windows VM; and all source builds reproducibly from your README. If you have questions about workflow details or UI preferences, feel free to ask early so we can lock decisions in before coding begins.