php send mail from localhost

You must change the php.ini file:

[mail function]
; For Win32 only.
; http://php.net/smtp
SMTP = localhost
; http://php.net/smtp-port
smtp_port = 25

; For Win32 only.
; http://php.net/sendmail-from
sendmail_from = you@yourdomain

It won’t work if localhost is set, for that reason change to your mail server.