Twinfield is an online accounting system for entrepreneurs and accountants. The Twinfield iPhone app helps people in an easy and fast way to register hours, to keep mileage records and to submit declarations. With a few clicks, the data will be sent to an online administration and an invoice can be sent immediately. The Twinfield iPhone app saves time; filling out paperwork is not necessary anymore. The Twinfield iPhone app makes full use of the features of an iPhone.