i am facing a problem using php mail() function [duplicate]

I got a contact form from google and try to use the php mai() function. this the error I get: ( ! ) Warning: mail(): SMTP server response: 530 5.7.0 Must issue a STARTTLS command first. y15sm903941wro.68 - gsmtp in C:\wamp64\www\a.php on line 30

this the a.php file:enter image description here

and this is the configuration i used in my php.ini file:

; For Win32 only.; http://php.net/smtpSMTP = smtp.gmail.com; http://php.net/smtp-portsmtp_port = 587; For Win32 only.``; http://php.net/sendmail-fromsendmail_from ="yo.thiam@gmail.com"

please help me