The classic formal portrait lighting is a high and wide main light (meaning up to about 45 degrees high and up to about 45 degrees from the side) of the subjects' faces. Should be a great near light to be soft (umbrella or softbox).
The fill light is about 1 lt less bright (brightness ratio on the subject) and frontal, that is, as close as possible to the lens (to fill the exact shadows visible by the lens without creating another set of shadows). A flash on the claw can do it. The big lights (umbrellas) are of course softer, but the softness is not a problem for a flat front light that does not create shadows (on the face … so close to it). axis of the lens, any shadow behind should be hidden behind the subject).
The third light may be behind the subject on the bottom, or may be a light of hair.
My site has a page that could clarify, at https://www.scantips.com/lights/setup/