If you are using Epson Receipt Printer (TM U220, TMT82 and TM-T88V) you need to setup your printer to avoid getting wasted paper caused by Header and Footer printing.
Please follow below instruction depending on the browser you use
Chrome Print Setup
Type Ctrl + P (Print), Make sure Headers and Footers is not clicked
Firefox Print Setup (Print - Page Setup)
Specify Zero Margin and Blank Header & Footer