How does direct path load work when dataguard is enabled?

Question

There's a few posts about direct path and dataguard but I just want to understand exactly how it actually works.

How maybe I made an incorrect assumption, but if direct path means it writes to the data files (as per the docs) then doesnt that mean no redo is generated?

And if no redo is generated then how does dataguard work? ( which is soley based upon transferring redo to the standby machine right? )