The top part of the foot is called the dorsum. When the dorsum of the foot moves towards the body, this movement is called dorsiflexion. When you are sitting with your legs outstretched and you bring your foot and toes towards your body, you are dorsiflexing. When you are sitting in a chair and you raise your foot while your heel is planted on the floor, you are dorsiflexing.
Plantarflexion
The bottom part of the foot is called the plantar surface. When the plantar surface moves away from the body, this movement is called plantarflexion. When you are sitting with your legs outstretched and you point your toes away from your body, you are plantarflexing. When you are sitting in a chair and you raise your heel while the ball of your foot is planted on the floor, you are plantarflexing. If you are standing on tippy toes, you are plantarflexing.