PHP mail function goes to spam not inbox

Hello,

I want to send an email using the PHP mail function not SMTP (I know that is not good practice but the Client request that).

the emails go to the junk/spam folder is there any way to make it goes to the inbox as a normal email?

I tried the solution here //stackoverflow.com/questions/5935087/how-do-i-prevent-mails-sent-through-php-mail-from-going-to-spam

but it goes to junk 

here is my code 

$to_email = 'to@domain.com';
$subject = 'Testing PHP Mail';
$message = 'This mail is sent using the PHP mail function';

$headers = "From: myplace@example.com\r\n";
$headers .= "Reply-To: myplace2@example.com\r\n";
$headers .= "Return-Path: myplace@example.com\r\n";
$headers .= "CC: sombodyelse@example.com\r\n";
$headers .= "BCC: hidden@example.com\r\n";
 
mail($to_email,$subject,$message,$headers);

any help please