This method is not foolproof as it cannot account for changes in page numbers caused by adding more text than fits on the page or by removing text which changes the numbering of the pages in the document. The date applied to the page will be retained on that page even if the page content has changed by virtue of what went before.
To attempt to overcome that limitation it would be necessary to insert a section break after each relevant section and use instead the {Section} field. The field construction below would be inserted in each header/footer of the document (or the section header/footers) must be linked to ensure that the field appears in each.
The above field construction will, when first entered, show the Createdate field value as the docvariables will not be present.
{ IF { DOCVARIABLE { QUOTE varPage{ SECTION } } } <> "" "{ IF { DOCVARIABLE { QUOTE varPage{ SECTION } } } <> "Error*" "Page updated - { DOCVARIABLE { QUOTE varPage{ SECTION } } }" "Page created - { CREATEDATE \@ " d MMM yyyy" } }" "Page created - { CREATEDATE \@ "d MMM yyyy" }}
When changes are made to the section, running the following macro will save the changes, create the docvariable and update the header to display the following, the date being the date the macro is run.
To use the version with page fields rather than section fields, move the apostrophe from the line
i = Selection.Information(wdActiveEndPageNumber)
to the start of the following line
If you don't know how to use the macro code see - https://www.gmayor.com/installing_macro.htm
It is a frequent requirement for documents, especially manuals, to record the last date that a particular page was updated. This is not that easy to do, as Word is not a page layout application and 'page' is a rather vague concept, created by the flowing of text within the current margins. However on thinking about the problem, it should be possible to work around this by taking advantage of the {Page} field which would enable you to increment docvariable fields, so you could introduce a docvariable field to the header/footer, which would allow the same field construction throughout the document.