How to create a drop down box in Excel

Hi,
I have an Excel application that is just a simple crude database for my coffee shop. There is a form which takes order and prints the Receipt. We have 3 types of coffee in the shop and we are increasing. Currently, in the form we have to add the whole name “Black” , “Light”, in the type field to create the receipt properly.
I want a drop down box there which will have all the types, so I can just select it from there. How can I do this? I am not an Excel expert, nor even a programmer. I hired a student to make this Excel file for me which I copy-paste every year.
I can see the code and that is very interesting! So I thought that maybe I can do this little tweak. It may be possible if you help!
