<?php 
//get data from form  
$form_subject= "this is subject of the mail";
$form_message= "this is message body of the mail";

//fixed recipient details
$mail_to = "sendtothisemail@abc.com";
$mail_from = "fromxyg@xyz.com";
$mail_subject =$form_subject; 
   
# Open a file  
  $file = fopen("contact.txt", "r" );//change your file location  
  if( $file == false )  
  {  
     echo "Error in opening file";  
     exit();  
  }  
  # Read the file into a variable  
  $size = filesize("contact.txt");  
  $content = fread( $file, $size); 
  
  # encode the data for safe transit  
  # and insert after every 76 chars.  
  $encoded_content = chunk_split( base64_encode($content));  
    
  # Get a random 32 bit number using time() as seed.  
  $num = md5( time() );
  
  
  # Define the main headers.  
  $header = "From:xyz@example.com ";  
  $header .= "MIME-Version: 1.0 ";  
  $header .= "Content-Type: multipart/mixed; ";  
  $header .= "boundary=".$num." ";  
 
  //START- Encoding attachment for mail
  # Define the message section
  $message = "--".$num." ";  
  $message .= "Content-Type: text/plain ";  
  $message .= "Content-Transfer-Encoding:8bit ";  
  $message .= $message." ";  
  $message .= "--".$num." ";  
  
  # Define the attachment section  
  $message .= "Content-Type:  multipart/mixed; ";  
  $message .= "name="test.txt" ";  
  $message .= "Content-Transfer-Encoding:base64 ";  
  $message .= "Content-Disposition:attachment; ";  
  $message .= "filename="test.txt" ";  
  $message .= $encoded_content." ";  
  $message .= "--".$num."--";  
   //START- Encoding attachment for mail

  # Send email now  
  $result = mail($mail_to, $mail_subject, $message, $header);  
  if( $result == true ){  
      echo "Message sent successfully...";
     // header("Location:contact.php"); uncomment to go back to other page
   }else{  
      echo "Sorry, unable to send mail...";  
   }