Data entry or data processing can be any type of computer process which performs the conversion of data into knowledge. The processing is generally thought to be automatic and working as on a computer. As data shows maximum utility when it is displayed in an organised manner and actually imparts knowledge of something, data processing structures are generally called as information systems to put focus on their practical aspect.
Nonetheless, both the expressions are somewhat similar, carrying out similar functions; data processing systems generally make use of raw data into knowledge, and similarly information systems generally make use of raw data as input to generate information as a result.
In a more general context, the term can be applied to any procedure wherein there takes place a conversion of data from on form to another.
A data is the word and figures that we enter in the computer through a input device like mouse, keyboard, etc. All the work we done at the computer is called data in computer language.
Data entry is the part of computer the performs the conversion