I just noticed that the email sent from my host using mail() function also sends the internal data in headers.
For example, here is this what I found in Gmail (by clicking on show original),
X-AntiAbuse: This header was added to track abuse, please include it with any abuse report
X-AntiAbuse: Primary Hostname - abc.hostname.com
X-AntiAbuse: Original Domain - domainname.com
X-AntiAbuse: Sender Address Domain - abc.hostname.com
X-BWhitelist: no
X-Source: /usr/bin/php
X-Source-Args: /usr/bin/php /home/michael/mail/script.php
X-Source-Dir: example.com:/michael/mail
X-Source-Sender:
X-Source-Auth: michael
X-Email-Count: 0
X-Source-Cap: ZsiufdyrnciuyixcioobQ==
How can I remove then from sending in any email headers?
You can’t do much against it, since the header is added when the mail is going out. As long as there isn’t a real reason why you don’t want these additional headers, you’ll have to live with it.