Why do I not get a “sent” mail record. How do I know mail was delivered
Most servers do not process delivery receipts, even if you specifically ask for them, but you can always assume that the message has been delivered unless you get a notification that it has not.
Also there will be a sent message in your Sent folder. That will only be there if the message was successfully uploaded to your server. After that, if the message could not be delivered to the recipient, you will get a notification from your email provider. Otherwise, it has arrived successfully at its destination.