If you want to add a ComboBox to one of your worksheets, in order to hace some additional options (drop-down list), here's the procedure:
First you must create the list of items you want to have in your ComboBox:
In our example we will make use of a list of the types of websites/blogs.
Create this list somewhere on your worksheet,(e.g From cells: E13-E17)
Activate the Developer Tab:
Office(orb) button/Excel Options/ POpular / check Show Developer tab in the ribbon.
Click on the Developer tab
In the Controls Section click on the Insert button and select the Combo Box tool.
You'll notice that the mouse pointer changes to a small crosshair.
To create the combo box click and drag the mouse button on an empty space of your work sheet. Once you obtain the desired size (height X Length) release the mouse button and the combo box will appear in your worksheet.
Right-click on the combo box/Context menu appears/ select the last option Format Control
In the windows that open simply input the cell range define earlier (list of options to be displayed in the combo box).