If you're creating a sheet that requires users to enter data, you might want to restrict entry to a certain range of dates or numbers, or make sure that only positive whole numbers are entered. Excel
can restrict data entry to certain cells by using
data validationAn Excel
feature that you can use to define restrictions on what data can or should be entered in a cell, and to create messages that prompt users for correct entries and notify users about incorrect entries., prompt users to enter valid data when a cell is selected, and display an error message when a user enters invalid data.
Do any of the following:
Restrict data entry
Prompt users for valid entries
Display an error message when invalid data is entered