Mail flow is like this

Most of the header analysis tools are online.  Put your Outlook headers in here (below) and see what it tells you.

https://mxtoolbox.com/EmailHeaders.aspx

If your entry reflects all the received: lines
This means the email was submitted through the web interface.
Commonly, there is an identifier in the headers that MS can use to determine the source, ip, credentials, user who sent the message.

If you can post the entire message header, I can point out what to look for in a message header and how to determine the flow..

As arnold mentioned, that's not even close to all of the headers. Please post everything that you have if you're comfortable sharing.

that is why I suggested a proper header analysis tool. not enough here

Run the header in this tool https://testconnectivity.microsoft.com/?tabid=mha

I cant share the complete header details as its confidential but i ll give u the history that i am receiving email from different sources to defame the company top management.

I have only email header   but no logs from mail server mail gateway and Firewall

I need to find

sender location not the location of gmail or protonmail
tracking the sender email either its genuine when it was created who own this email etc etc
getting maximum details about the person behind this activity
Delivery-Information.docx

Protonmail is designed very much around privacy, so good luck on that. Plus they definitely don't record IPs in the headers.

Gmail doesn't stick in the origin IP either.

Going through the legal system is really going to be your best shot.

Here is how thing work
The top most Received: headers is the last added
The Received: header closest to the From: entry is the first added.

Received: from source
                  by the system that added this header and tim


In short you are tracing up, making sure that the source matches the prior receiver. If they do not match, the header below is fake.


Received: from source1
              by source  on today
Received: from source3
             by source2 yesterady

The originating, lowest most Received: line can be seen as a fake since the next addition of a Received line reflects source1 as the source of the message delivered to the one adding the Received: entry

Commonly in most of the current web based email submissions, they have an X-something: header that has some funny characters. only they can decrypt the reference to identify the sender, username, IP, etc.

See if they have an abuse department, provide the header message to that department with the complaint.

They should adderss the issue with the party.