Security Considerations for Creating Email on the Internet

Question

I know that I should consider entering a mail header ,

and is there anything else that I need to know before I create mail?

I want mail, and I feel that I have to create a form mailbox
on my page, but I heard that mail is a dangerous thing if I do not take into account all the security things.

Answer 1

1- avoid spam, use captcha or other thing to prevent spam.

link about it: are you human? (or How to prevent spam)

2 - Prevention of duplication of materials