Comprehensive Excel GST Invoice System

I'm seeking an Excel expert to create a comprehensive GST invoice system tailored for my service-based business. The system should be user-friendly and automated, with the following key features:

- GST/invoice generation with auto Invoice Number
- Detailed invoices including tax breakdowns
- Additional notes or terms on invoices
- Purchase Book
- Sale Book
- Profit and Loss reporting
- Employee Salary Management
- Backup for Invoices
- List of Billable Items

Ideal Skills and Experience:
- Proficient in Excel
- Experience with GST and invoicing
- Strong attention to detail
- Ability to create automated, user-friendly Excel systems

Please provide examples of similar work done.