Why are there several letters in the wrong PHPMail encoding?

Question

Character encoding

The code is encoded:

$headers .= "Content-type: text/html; charset=utf-8\r\n";
+
$mail->CharSet = 'utf-8';

But slips such 2-3 letters in all letters!
скоÐ �іюйтеналÐ �штуваннях
I tried these options together and separately, it doesn’t help - maybe you need to configure them separately?
(Ubuntu server)

$message = iconv("UTF-8", "WINDOWS-1251", $message);
$message = mb_convert_encoding("UTF-8", "WINDOWS-1251", $message);
$message = mb_detect_encoding($message , mb_detect_order(), true) === 'UTF-8' ? $message : mb_convert_encoding($message , 'UTF-8');

Answer 1

In fact, the question is relevant to this day. In the letter, the formatting and text are normal, but this is the same as in the picture in each letter.

Answer 2

>You need to make it with html code, but nothing works... poke pliz!
What does it mean to make html code?
This?