How do select and save my choice in Drop-Down Form in word?

I have a form to fill in word. This form has a select option. When I double
clik the select another window opens up. It has a drop down list to select.
When I select the option it does not show up in the word document.

Without knowing how the form was designed, it is not possible to tell you
how to do this. Try contacting the supplier of the form.