How the store's emails leave and a log of each one: Magento's transport, Amazon SES through its API with the server's AWS role, or none. Marketing > Communications > Email Log shows every email with its status, lets you open it and resend it. Test addresses are logged, not sent.
The email log in the admin.
What it does
Amazon SES without SMTP credentials
Email log with Resend
One sender for all emails, a Send Test Email button