IF she is on or near the surface of Earth at the time, then ...
... Her WEIGHT is (mass) (gravity) = (72 kg) (9.8 m/s²) = 705.6 Newtons
... The surface under her feet exerts a normal force, upward,
against her feet.
... If the upward normal force is NOT 705.6 Newtons, then the
NET force on the bottom of her feet is not zero, and her feet are
accelerating, either up or down.
... But she is just standing there, not accelerating either up or down.
... Therefore, the NET force on the bottom of her feet must be zero.
... The normal force acting upward against her feet must be exactly
equal to her weight ... 705.6 Newtons.