How to make a greeting after the /start command in a Telegram bot?

Question

PHP

How to make a greeting after the /start command in a Telegram bot? So that after this command my message comes out

Answer 1

A bit of shitty code). Suitable only for my case where only two encodings are possible

<?php

$str = "╨С╨░╤В╤М╨║╨░ ╨Ф╨╕╨│╨╗╨╛╨▓";

$ret = iconv("UTF-8", "CP866", $str);

echo var_dump(strlen($str));
echo var_dump(strlen($ret));

if (strlen($ret) < strlen($str)/2) {
  echo "New " . $ret;
} else {
  echo "Old " . $str;
}

Answer 2

php.net/manual/en/function.mb-detect-encoding.php#...

Answer 3

You probably need to write the code for this bot somewhere, add a handler there that will respond to commands and somehow respond to messages. Well, run it somewhere.
Do you have a bot yourself? Or is it just a theoretical question?