how to convert characters to numbers in word

First, hold down the ctrl key in the blank of the document, press F9, and enter SEQ \A in the curly brackets that come out, which is {SEQ \A}, [note that there is a space after SEQ]; then select the field and cut it;
then Find→Find Content→##→Replace with→^c→Replace All; finally ctrl+A, press F9.
So far, you're done.