when we receive money and a sales invoice is fully paid - if we wish to make a PDF copy by going to print as the customer is requesting a paid invoice copy why do I get a three page invoice?
There are known problems with PDF generation. You can search the forum to read all about it. Fixes have been promised for quite a while. Workarounds are mentioned in the various threads.
See Problems with printing to PDF
Try emailing the invoice to yourself.