In the equation \( y = f(x) + k \), the term \( k \) affects the graph of the parent function \( f(x) \) by causing a vertical shift.
- Shifts Up or Down: If \( k \) is positive, the graph of the function moves up by \( k \) units. If \( k \) is negative, the graph shifts down by \( |k| \) units.
The value of \( k \) does not affect horizontal shifts (left or right), reflections across the axes, or any other transformation. The transformation is strictly vertical.