Validate Data in EXCEL using Validation List
Excel enables you to restrict the values a user can enter in a cell. By restricting values, you ensure that your worksheet entries are valid and that calculations based on them thereby are valid as well. During data entry, a validation list forces anyone using your worksheet to select a value from a drop-down menu rather than typing it and potentially typing the wrong information. In this way, validation lists save time and reduce errors.
To create a validation list, type the values you want to include into adjacent cells in a column or row. You may want to name the range. After you type your values, use the Data Validation dialog box to assign values to your validation list. Then copy and paste your validation list into the appropriate cells by using the Paste Special Validation option. You may want to place your validation list in an out of the way place on your worksheet or on a separate worksheet
Validation lists can consist of numbers, names of regions, employees, products, and so on.