1. Under the Data tab, select Data Validation .
   
2. Select Create Validation from the contextual menu.
   
3. Select the range of cells you wish to apply data validation.
   
4. Under Criteria, choose an option and set your conditions, such as a list, text, or cell range.
   

You can choose a list of values that will be entered into a particular column before using data validation. There will be a drop-down list displaying the values you have chosen and you can pick your value from the available list.

You can also set a legend near a particular cell that uses data validation to regulate its data and a warning error alert when the data validation condition is not followed. This can be done from the Data Validation box.

 

Edit data validation conditions

1. Under the Data menu, go to Data Validation > Manage Validation.
   
2. In the Manage Validation window, select the rule you wish to edit.
   
3. Click Edit, Copy, or Delete to modify, duplicate, or remove the rule, respectively.
   

Clear a data validation condition

1. Select the range of cells that you wish to remove the data validation rules from.
   
2. Click on the Clear option in the tool bar.
   
3. From the dropdown, select Clear Data Validations.
   
4. Alternatively, select the rule you wish to delete in the manage validation window and tap the - button to delete the rule.