Google Sheets Expense Tracker Formula

I'm looking for a skilled Google Sheets expert to create a formula for tracking expenses. The main goal is to automate and streamline the process of categorizing expenses.

Requirements:
- Create a formula that automatically categorizes expenses based on predefined categories
- Ensure the formula is easy to use and integrates well with existing sheets
- Provide clear documentation on how to use the formula

Ideal Skills:
- Advanced knowledge of Google Sheets and its formulae
- Experience in building financial tracking tools
- Attention to detail and strong problem-solving skills

Please include examples of previous work in your bids.