I keep forgetting to post this incredibly useful reference for creating fields in Word that do about everything you can think of with dates:

http://www.gmayor.com/Zips/DateCalc.zip

You need to toggle field codes and update the fields in the DateCalc Word document in order to use it as a learning tool, but it provides you model fields to do about everything you want to in Word involving dates.

I'll give you a couple of common uses for this info and a sample document demonstrating them to get your creative juices started:

I've used his Calculate a day, date, month and year, using n days delay, to set up a Quote field for yesterday's date, then saved that as a formatted AutoCorrect entry.

I've used his Calculate the # Years Months & Days Difference Between Two Dates to set up a quote field that calculates a patient's age in years from the date of service and patient's birthdate (bookmarked in my documents as dos and dob), or inserts a blank if there is no birthdate. That's also saved as a formatted AutoCorrect.