• Login to Magento backend
  • Go to the System->Configuration menu ( Magento 1.x ), or Store -> Configuration ( Magento 2.x ).
  • On the left hand menu under the Advanced tab (at the bottom) select the System menu item.
  • Select ‘Mail Sending Settings’ from the selection on the right hand side.
  • Set Disable email communications to ‘Yes’, then no email will send through Magento.