Unfortunately, Word has no built-in function that will do the conversion, but you can create a macro that will help you to transform the number to words. If you already have a document that contains numbers, click in front of the number, press Ctrl + F9 key combination, copy the number in the {} brackets and add = sign in front of it. After that, add *cardtext and press F9. The number will appear in words. If you want to change the number, right-click on the entry and select Toggle Field Codes.