Sony FX 6 Quick Start Manual page 91

Focusing: Other focus area options
The Menu/Shooting/ Focus/Focus Area specifies the target for the
auto focus operation (and PUSH AUTO focus in Hybrid mode).
By default it is set to Wide. This is the least precise option.
You can also specify a Zone, that is somewhat more precise. Specifying
a zone might be a good idea when filming a stage, for example, where
all the subjects are on the same plane.
But, I am recommending using a Flexible Spot because usually there is
a single subject that is the centre of your focus.