You can insert a hyperlink to the document PDF Footer/Header/Letter Footer messages by going to the document, click "Create PDF"
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Click Expand on Header or Footer Message.

Click on Add New to create a new Header/Footer message template. you can save them for later use.
Select the Hyperlink function, insert hyperlinked text and its link into the fields, click Save.

After adding the additional hyperlinked message(s), click Save Customization and it's done.