Hi Valeria,
Try the attached copy of your 'ex1 label' document. What I've done is to move all your content into the page header. At the moment, it's just a proof-of-concept demo, based on the code from:
https://www.msofficeforums.com/word-vba/12959-sequential-document-numbering.html#post34477
If the approach taken meets your needs, we can modify the code with your macro wording, etc, then add just the code to a template that you could attach to all your documents so that they wouldn't need to each have the same code and could be saved as .docx files.
If you examine the code, you'll see there are some lines commented-out. For production use, those lines could be made active so that, amongst other things, the printout happens automatically - a different approach could be taken to work through the print dialogue if you prefer. The commented-out line to update the page # means that, next time the document is opened, the starting number would always be one more than the finishing number from the time before.