Sony FX 6 Quick Start Manual page 96

Focusing Recap: Two Auto Focus Types
When you see the orange square in the VF then the camera is in flexible spot
auto focus, or, if you like, the regular auto focus with the flexible spot option
chosen.
When you see the white square following an object, or the white squares
following a person's eyes, then the camera is in auto focus tracking.
Be careful. If you see a white square following a person but in addition an
orange square then the camera is in total auto focus mode, but still in the
flexible spot auto focus. It is tracking the person, but not applying the
tracking data. It is not changing the focus to that person. There should be no
orange square in the VF when in auto focus tracking.
Press button 3 on the side of the camera to exit flexible spot auto focus and
then press on the subject/object to track with your finger on the VF.