He rightly pointed out the standard functionality of the BP30, which performs the same actions. I'll quote from the comment:
Personal settings - Email settings - Send copies of outgoing emails to the address.
illustration of the above:
In short, I invented the wheel. You don’t have to download the extension but use the standard functionality.
Brief introduction
Different mail servers behave differently regarding emails sent via SMTP. If you have mail on gmail, then the problem described above most likely does not concern you. I have mail on Yandex and, if nothing is done, then after sending a letter from BP 3.0 the fact of this very sending is lost without a trace. On the Internet I found a tip to forward letters to yourself, indicating the address in the “Bcc” field of the letter. On the side of your mailbox, you can set up rules for parsing letters and move a letter that comes from yourself to the “Sent” folder.
It turned out that YandexMail by default moves letters to the “Sent” folder if the e-mail address of the account (i.e., your own e-mail) is in the “bcc” field of the letter.
How it works
If the extension is already installed, then send a letter to your counterparty in the most usual way, for example, from the document or register of documents “Invoice to buyer”
In the form for sending a letter, check the “Send to Sent Items” checkbox to forward the letter to yourself (the checked box will be remembered for the current user)
Feel free to send a letter.
It will reach the counterparty.