Known to originate email on behalf of other domains? no
Preserves DKIM signatures? yes
Uses own domain in envelope (SPF)? no
Notes on Forwarding
Microsoft runs a complicated infrastructure, with email routing through and between various services on route to final delivery. For an overview from Microsoft on their forwarding challenges, see https://blogs.msdn.microsoft.com/tzink/2016/05/19/why-does-my-email-from-facebook-that-i-forward-from-my-outlook-com-account-get-rejected/
When deploying DMARC, domain owners often find that email can flow through forwarders before arriving at a final destination.
Domain owners then wonder if the forwarder is capable of interoperating with DMARC.
This directory contains information on the capabilities of various email forwarders.