PHP表单在垃圾邮件中发送电子邮件并且有问题，刷新页面再次发送电子邮件[重复]

Question

This question already has an answer here:

• How do you make sure email you send programmatically is not automatically marked as spam? 22 answers
• Simple Post-Redirect-Get code example 6 answers

I uploaded code on server, whan i send ain on mine outlook email, email is put to spam folder, same problem is when i refresh page, mail get sent again. Can anyone help me out with code? Forword, Thank you very much!

</div>