Data capture is the process of getting the data required for processing.

There are a number of different methods of data capture :

Forms and questionnaires		The design of data capture forms is important. They must... be clearly laid out; have clear instructions; have no ambiguous questions; have examples for 'tricky' questions be designed to make it easy to transfer data into a computer system
Automatic data capture	Bar code scanning; OMR (mark sensing); OCR; MICR	Methods which do not involve keying in data. As little human intervention as possible - humans generally muck things up so this is a good thing!
Data Logging		Sensors regularly measure a physical quantity and send it to be stored on a computer.

It is important that data does not have errors. A lot of time is spent on methods of eliminating data errors.