Invoice2go

Invoice2go, now part of Bill.com, is a mobile-first invoicing and payment app with growing accounting features. It excels at creating and sending professional invoices from your phone, with options for recurring invoices and online payments. It also includes basic expense tracking, time tracking, and client management. Its accounting capabilities are lighter than full suites, focusing on the cash-in side of the business.

It's perfect for freelancers and tradespeople who are constantly on the move, need to invoice clients immediately after a job, and want a simple way to track what's owed and what's been paid, all from a mobile device.