I used the procedure mentioned in the following link and combined it with my code:
https://www.msofficeforums.com/word/...iple-docs.html
But it seems that it is not working. I think the idea of saving the last number is good but where can I save it? The document property seems does not working in my file? I put it in the header to be able to remove the colour and make it sightless, attached is the file. BTW thanks for putting the code in appropriate tags since I could not see it at the first.
I think I should try to find the answer to question What other ways can I save the last generated number?