How does php send HTML-format EDM emails?

There seems to be no relevant code on the Internet. I can see the EDM email sent by sf. I don't know how it works. I feel like I have no idea how to use the mail provided by php, it seems that there is no relevant code on the html code website. I can see the EDM email sent by sf, but I don't know what the related principles are used. I don't feel like I have any idea.

Using the mail provided by php, the code is directly converted into html code.

Reply content:

There seems to be no relevant code on the Internet. I can see the EDM email sent by sf. I don't know what relevant principles are used for this. I feel like I have no idea.

Using the mail provided by php, the code is directly converted into html code.

The php Manual contains examples of sending HTML emails:

   Birthday Reminders for August  
Here are the birthdays upcoming in August!
  
 
 
    
  
  
 
   
 
    
Person
 
    
Day
 
    
Month
 
    
Year
 
   
 
   
 
    
Joe
 
    
3rd
 
    
August
 
    
1970
 
   
 
   
 
    
Sally
 
    
17th
 
    
August
 
    
1973
 
   
 
  
 
 
';// To send HTML mail, the Content-type header must be set$headers  = 'MIME-Version: 1.0' . "\r\n";$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";// Additional headers$headers .= 'To: Mary 
 
  , Kelly 
  
   ' . "\r\n";$headers .= 'From: Birthday Reminder 
   
    ' . "\r\n";$headers .= 'Cc: birthdayarchive@example.com' . "\r\n";$headers .= 'Bcc: birthdaycheck@example.com' . "\r\n";// Mail itmail($to, $subject, $message, $headers);?>
   
  
 

If you use the mail function, you can use a mail proxy such as sendmail, postfix, and exim.

Or use the smtp library phpmailer.