My question is of genuine conversational interest - 'free will' is a fascinating coin, as it conflates unrelated (yet independently valid) theory into broad, fuzzy existential 'slang'.
From a religious stance, I get that 'free will' is a generally viewed as an act of divine grace imparted as a methodology to assert our respect for God, while pursuing a reality that actively seeks to encourage awareness of His message. A spiritual symbiosis, fusing intellectual awareness with humble self-deprecation.
If we are speaking in terms of biology, 'free will' is just another way of describing the evolving eminence of our brain over time. We began this process with simple impulse regulation centers (thalamus; brain stem; mid-brain) that eventually evolved into structurally-complex, connection-rich neurological ecosystems (Frontal Cortex) that functionally cooperate with the 'older' parts of our brain to conceive a creative, reasoned awareness of ourselves and our world.