no i don't believe the processing history of the image is stored in the XISF. the closest thing is that some preprocessing processes that generate images (like ImageIntegration) will write some info about the input images to the FITS header of the image.
activate the view, right click and choose "load history explorer"
open history explorer from left tab, drag triangle to desktop, thus creating a process icon
you can name the process icon if you like (click the little N)
right-click the process icon and select "save highlighted process icons"; choose a place and give it a name
you can attach the .xpsm file created to an email. make sure to tell whoever you are sending it to what workspace it is on and also to be sure to use the "merge process icon" command when loading it in their pixinsight. otherwise all of their process icons will be deleted as PI opens the new one!