I always test using my own email as the recipient address. That way when you get the emails from the form, you know it's working. Then just change the email in the PHP from your's to the email that it should be sending to.

You can also test it by sending a copy (bcc) of every email to your own email address during testing. It would be clever to create a new gmail account for that purpose

$headers = "From: me@mydomain.com"; //sender
$headers .= "\r\nCc: copy@$adomain.com"; //copy to
$headers .= "\r\nBcc: bcc@$adomain\r\n\r\n"; //bcc to <---this it the important one for testing your mail function
$headers .= "\r\nX-Mailer: PHP/" . phpversion(); //sending mail client

mail($to,$subject,$message,$headers);

Hope that helps

Is there two topics for same issue? I guess I already answered.

That means the function returns Boolean (True/False) after sending mail. If it succeeds, it returns TRUE otherwise FALSE.

Hope that helps!

The mail() function returns false if there was an error, so you can capture the return value in a variable and then branch based on its true/false value to add in error handling/logging.

WARNING! be aware that this only tells you that mail was successfully accepted for delivery by whatever server is configured as the SMTP server for your mail setup. If the email has to go through multiple hops to reach the destination, there could be errors along the way that you won't catch. It's always a good idea to send a few test emails, preferably to multiple host destinations, before saying you're good.

yes...this can be checked using an if - else condtion

I like to create a log file that can be turned on and off.

I use it during development and then turn it off once the code moves to production, but I can always turn it back on quickly if I need to do some debugging.