I agree that more information is needed.

These documents likely should be templates if they are reused with an changing information.

One of my favorite methods of changing information in multiple templates is the use of AutoText and AutoText fields. The AutoText would be stored in a global template. It then populates documents based on the template.

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However, that would require that the person making the change know to save the changed text as the AutoText entry. The includeText field would work but the person making the change is going to need to know which document to use to make the change, the source document.