Working with other people on the same Excel file can be challenging. Especially when you prepare an Excel workbook and another person has to fill in some data. In such case, you probably want to make sure that only your intended values are possible to enter.
You are creating an Excel sheet, in which another user has to enter text data (for example, the name of a person or a place). Such texts can be misspelled easily. To prevent misspelling, you can provide drop-down lists, from which the user can select. The user can also simply type text, but the text has to match exactly one of the items on the list.