How to use DKIM with phpMailer?

Question

PHP

Hello! I'm trying to set up sending emails from the server through phpMailer. Letters are sent, but sometimes they come in spam, sometimes they are marked "failed to verify the domain."
I read this instruction https://gaalferov.com/blog/nastrojka-dkim-spf-phpm... I looked through a bunch of sites with manuals, but everything is somehow superficial. Even the link above is general phrases.
Maybe someone has a complete and up-to-date instruction from a to z for setting up DKIM + phpMailer? I also found several questions on this topic on the toaster, but there are no answers either ...
Most of all, it drives me into a stupor that with such a massive use of phpMailer, the author makes changes to the mailer class using the link above, did the developers not provide for the use of this DKIM

Answer 1

And what is difficult?
www.stackoverflow.com/a/24464694/1603055
DKIM is usually configured on the server, not in code. sent through a local mail server.
And the second part is sent through services that take care of it themselves.
Therefore, no one in the code is a crutch, because no one needs it.