Insert Custom Message Header value in an email

[Admin O365]

Hello,

Environment: Exchange Online

Is it possible to Insert Custom value in the Message Header of an email?

Regards,

Dematri

[#2]

Yes, via Transport rules: https://docs.microsoft.com/en-us/exchange/security-and-compliance/mail-flow-rules/mail-flow-rule-act...

[#3]

Thanks Vasil....

Sorry I should have added earlier - 

Is it possible to add the sender address to an existing message header value (type: X-Protective)

Here, sender address will change based on the sender id.

Any suggestion will be of great help.

[#4]

In general yes, but depends on the header. Some headers will be stripped/overwritten by the server, you cannot for example "forge" and antispam header, etc.

[#5]

Any article that you shared that provides the approach of how to get it tested?

[#6]

there are some examples in the article above.