If a person is walking on a level path in a straight line at constant speed the total kinetic energy is constant, so no total work is done.
The external forces acting on the person are gravity downwards, the normal force of the ground pushing the person upwards, friction with the ground pushing the person forward, and air resistance pushing the person backwards.
In a simplified analysis we would assume the person does not move vertically at all. In this case friction and direction of travel are in the same direction so the force does positive work, while air resistance and direction of travel are in opposite directions so that force does negative work. Total is zero.
If we ignore air resistance so that friction is the only force, it does positive work when the person starts walking (increasing speed) and negative work when the person stops (decreasing speed). The total work done from start to end during the walk would again be zero.
In actual fact walking is a more complex activity than it appears. Start when the right leg is upright, the body is moving forwards and the left leg is moving past it. As the body moves forward it is also moving downward, and when the left (now the leading) heel hits the ground, it must first push backwards and upwards. At this time it is doing negative work. Next the right toes and instep push forward to lift the body over the left leg, doing (positive) work against gravity as the body rises. The cycle then repeats. The positive and negative work adds up to zero over several cycles.
We usually feel the force more as we drive forward with the back foot, though your legs will become tired as they absorb energy while you walk downhill. Even walking on level ground it doesn't feel as though no work is done because of the energy expended within the body as muscles contract and relax during the process.