I have googled this but cannot find a solution.

I want to produce multiple printed envelopes with the same wording. I do not have a letter to send. The application is in a small company and I have the standard wording to print on the envelope contained in a document on file. I highlight the wording in the document and then go into 'Mailings', 'Envelopes' to print the envelopes.
The wording is as follows
"Thingymajig Company
Payment to Cleaner No......
2015/2016'

Sometimes , I need to print 4 envelopes at one go. At the moment , I want to print 17 envelopes ....... all with the same information , apart from the actual 'No' of the envelope which I write on manually.

I am using Microsoft Word 2007. I have seen "solutions" which refer to 'Add to Document' button ... I don't appear to have this ! .... and I don't need a 'Return Address'

Can anyone please suggest a way of doing this ?