Like a checkbox?
Show the Forms toolbar
View|Toolbars|check Forms
you'll see the checkbox icon on that toolbar.
click it and then click where you want the top left corner to be. Drag down and
to the right. (If you make it too large, you can resize it later.)
Rightclick on that checkbox and choose Format|Control
Then click on the Control Tab. Put an address (like A1) to use for the cell
link.
You can use that cell in formulas to determine if the checkbox is checked or
not.
=if(a1=true,"It's checked","nope")