according to my book the perpendicular component of reaction force is called normal force when there is contact between two bodies. I can not understand that how for example when we jump we pushes the ground downward(action) and the ground pushes us upward(reaction) how this reaction is normal force? or for example if someone jumps to the shore from a boat, the boat moves in the opposite direction we push boat in backward direction and boat pushes us in forward direction(reaction) is this also normal force or friction force plz someone explain i dont understand.
Normal force in general is perpendicular component of force applied by surface on a body/System, In the context you are asking, When you jump, you use two component of forces to jump, One perpendicular to surface, Called "Normal force by surface" and and other is tangential to surface ,the friction, Which you use to move forward, as a vector sum of these force, you move up as well as forward, causing you to jump
In the situation mentioned, practically, you still use normal as well as friction to jump from boat to shore, In doing so, friction force on boat causes it to move in opposite direction of your jumping and normal force on boat causes the boat to move very little into the water, in other sense, water level rises around the boat..