You can save the common information in a file and use Insert > File,
choosing 'Insert as link' from the Insert dropdown. You can set links to
update automatically on opening and printing, but otherwise need to manually
update. (This method inserts an INCLUDETEXT field - you might want to look
at the Help for that - type INCLUDETEXT in the Help question box - to
understand the detail and other options such as inserting bookmarked parts
of a file.)
Another possibility is to save the common information in AUTOTEXT in an
attached template, and use an {AUTOTEXT} field - same issues about updating.
Other usual issues to think about are a) who is allowed to change the common
text and b) whether archived documents need links broken so they reflect the
text as it was when they were finalised, and not later changes.
