Hi Chriss,
Thank you for your interest in Syncfusion products.
Using DocIO its not possible to update the fields. In MS word only the fields can be updated by selecting the whole document (Ctrl +A) then press F9 to update the fields. For more information please refer the below forum thread.
http://www.syncfusion.com/support/Forums/message.aspx?&MessageID=77083Please let me know if you have any other questions.
Best Regards,
Bhuvana