Confirming to the customer.
WHAT MUST SEND
Order received Payment confirmed Dispatch notification Refund confirmation
WHY
A customer who receives nothing assumes failure, contacts you, or disputes the charge.
THE DELIVERABILITY PROBLEM
Shop emails frequently go to spam.
WHAT PREVENTS IT
Sending from your own domain SPF and DKIM configured Not using a free email address as sender
CHECK CPANEL EMAIL DELIVERABILITY
It reports whether your records are correct.
WHAT TO INCLUDE
What they ordered What they paid What happens next, with a timescale How to reach you
WHAT TO TEST
Place a real order and confirm every email arrives.
Check a major provider's inbox, not just your own domain.
WHEN TO RETEST
After any change to the site or email configuration.