HI! I have lease application in word ( all text ) that are static except for the top addresses that changes when I get a new building address to enter in.

I want these doc's to be in such a way that if I need to change something in the page ( Other than the address at the top ) that all the other "lease application's docs" that I have will change as well. I also need to be able to change the top part ( The address ) once only so this part can be normal or a space can be reserved to be normal space.

What kind of function am I looking for to accomplish this? Its a bit like a footer or header but for the rest of the 2 pages.