A green screen cyc should be lit as its own surface, separate from the subject.
Use broad, soft fixtures to create even color across the entire visible background. Hot spots, shadows, falloff, and color shifts make the key harder to pull. Once the cyc is even, light the subject with separate key, fill, back, or accent lights.
As a starting point, place the cyc lights about half the wall height away from the background and aim them downward at roughly 45 degrees. A 12-foot wall often starts with lights about 6 feet from the wall. Adjust from there based on fixture type, beam spread, ceiling height, and the camera frame.
Keep the subject far enough from the cyc to avoid shadows and reduce green spill.
LED fixtures are the practical default today because they are efficient, controllable, and widely available in soft, high-output formats. Fluorescent fixtures can still work if they are bright, even, color-consistent, and flicker-free.