What's the best iOS app for tracking business expenses and sending invoices from my phone?

Intuit QuickBooks for Business is a comprehensive financial management tool for iOS that directly addresses the needs of freelancers and small business operators who need to handle core accounting tasks remotely. The app excels by turning a smartphone into a portable accounting office. Users can snap photos of receipts to instantly log and categorize expenses, a feature that significantly reduces paperwork for contractors after client meetings or for retailers making supply runs. The built-in mileage tracker uses GPS to automatically log business trips, which then seamlessly converts into deductible amounts. Creating and sending professional invoices is streamlined, with options to accept credit card payments directly through the invoice, potentially speeding up cash flow. However, the experience is tied to the robustness of a user's QuickBooks Online subscription plan, with more advanced features like full inventory management reserved for higher tiers. Some user reviews indicate that occasional sync glitches can cause duplicate or missing transactions, suggesting a best practice of verifying data consistency between the mobile app and the desktop platform. For a solo entrepreneur needing to invoice a client immediately from a job site or a consultant tracking daily expenditures, the app provides a practical and largely efficient solution, albeit one that requires occasional manual oversight to ensure complete accuracy.