Notification email settings
You can configure the following for the notification emails sent to shoppers during the cancellation process.
Editing the templates
Go to Settings > Customer notifications > Templates > Cancellation

Click Edit on a notification to preview and edit its contents
※Each email comes with default wording that you can use as is. Customize it freely if you want to change it.
Setting the sender address
Set the sender (from) address for notification emails. Setting a sender address lets you see replies from shoppers to the notifications Recustomer sends.
Go to Settings > Customer notifications > Email sender > Cancellation / Returns / Try before you buy
Set the sender name
Enter the new address in the sender email address field and click Verify

A Verify domain dialog appears. Add the records it shows to the DNS records of your domain.

Once the DNS settings are in place, reopen the dialog from step 4 and click Verify domain
Reference: how to change records with major domain providers