Simple Invoicing is a free mobile application available on Android that allows users to create professional invoices quickly and easily. The app provides a simple, user-friendly interface that enables users to customize their invoices with their preferred currency, tax label, date format, and more. Users can also add customer details, invoice reference, description, and invoice amount. The app automatically generates a unique invoice number and calculates the tax amount and updates the total. Simple Invoicing also allows users to save their invoices in PDF format, email them in-app, or save them to Google Drive. With Simple Invoicing, users can create invoices offline and view and edit them later when they have connectivity. The app also builds a customer list for users, making it easy to invoice customers and select previous customers from a drop-down list.

Additionally, the app offers a Manage Invoices optional subscription, which enables users to review a list of their invoices, mark invoices paid, sort, view/edit, recreate/email, and delete invoices. The app also provides an Invoice Ad-free feature, which enhances the user experience. Simple Invoicing is compatible with phone resolutions of 480x800 and up, making it accessible to a wide range of Android users.