As you can see in that image, you can add headers to the XML element soapenv:Header, OR you can add it at the bottom with the green plus button.
But when you add a header using the green plus button, it is not added to the XML message.
So, what is the difference between both types of headers?
Thanks
As correctly explained in the comment of your question.
Here i have tried to give an example to explain the visual difference
Check out the circle things are the headers you added via the Green button i.e. they are the headers which will be not part of your XML
But they are the headers for the overall request. So its like metadata which would be helpful in knowing where to direct your request
header2: oktest
soapaction: www.test.com
But the header highlighted with Arrow is part of your payload i.e. XML which would be used by the application for processing the request.
</testns:header>
This you can see in the Raw tab of your request XML