Hi John,
Please try Paul's suggestion above to use the content control drop down in the header.
Additionally, I have another suggestion: Consider to use the Field code in Word. For example, if you want to insert the Office file name in Header. We can go to Insert > Quick Parts > Field. In the Field names list, select FileName, click OK.
Check if that is helpful. If I misunderstand your requirement, feel free to let me know.
Best Regards,
Winnie Liang
Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact:
tnsf@microsoft.com.

Click
here to learn more. Visit the dedicated
forum to share, explore and talk to experts about Microsoft Office 2019.