Excel Optimize

One of the most common and helpful uses for data validation function is to create drop down list in a cell, just like the figure below shows. Figure below shows month names with range A1:A12 as the list source.
To create that kind of drop-down list are:

1. Enter the list items into a single-row or single-column range. These items are the ones that appear in the drop-down list.
2. Select the cell that will contain the drop-down list and access the Data Validation dialog box.
3. In the Settings tab, select the List option and specify the range that contains the list using the Source control.
4. Make sure that the In-Cell Dropdown check box is checked.
5. Set any other Data Validation options as desired.

After you finished these steps you will get a drop-down arrow on the cell when it’s activated. Click the arrow and choose an item from the list that appears.