When you print, it prints the whole page. Would be nice to have a helper class that lets you specify what to print on a page.
eg:
https://preview.keenthemes.com/metronic8/demo1/apps/invoices/view/invoice-2.html

When you click print, it prints everything. In a real world situation, you would want to assign the 'print' class to the card and then everything else (app-sidebar / app-header / app-footer) etc, wouldnt print. just the actual invoice.
This would of course, also be handy in reports.