How to set canned text for multiple referral letters .(date, re: dear)

Typing 10 patient referral letters as 1 continuous document by same doc. Would like to have a way to put in canned text (date, Re:, DOB, sincerely) for each letter and then just fill the rest

Where do I start? What is the best way to get the canned text into a letter (autotext, macro, template, boilerplate... mind you I have NO IDEA WHAT ANY OF THESE THINGS ARE!) So far I have opened Word 97 and I'm stuck already.

Oh, did I mention I do this for 6 different doctors? So I am also wondering whatever I do, can I change the doc's name each day or would I have to have 6 different canned items. Here is what I need to use in each patient's letter.

Date:

Re:
DOB:

Dear Dr.

Sincerely,

Jane Doe, M.D.
JFD:tmt