Data entry is the act of transcribing some form of data into another form, usually a computer program. Forms of data that people might transcribe include handwritten documents, information off spreadsheets from another computer program, sequences of numbers, letters and symbols that build a program, or simple data like names and addresses. Some people perform jobs that are exclusively data entry, while others, like programmers, might have to occasionally enter data.
Since the advent of computers, and since the beginning of typing, the need to collect and neatly present documents has required data entry. Good typists, especially those who are also excellent at 10-key typing often are the most qualified for data entry positions. On the other hand, many computer programmers are not terrific typists but still plow their way through inputting code into programs when needed
People who work exclusively in the field of data entry are likely to be quick typists, able to read off longhand or typewritten documents, and must be accurate. In programming, the wrong letter, number or symbol can throw off an entire command function of a program. For spreadsheets or for documentation that will be published or printed, typos can result in misinformation or embarrassing errors.