A few XAMPP configuration points to send the email from PHP by using gmail account,
1, \xampp\sendmail\sendmail.ini
smtp_server=smtp.gmail.com
smtp_port=587
auth_username=huilin.xiong@gmail.com (your gmail account)
auth_password=your passowrd
2, \xampp\php\php.ini
sendmail_path = “\”D:\PHP\xampp\sendmail\sendmail.exe\” -t”
3, gmail account sign-in & security setting,
set Allow less secure apps: ON
If this is not set, the sending email will fail.