Typically targeting is taught to obedience or Schutzhund dogs later in their careers but we have found it useful to teach at the beginning. It leads on and can be taught exactly the same as article indication, and is a useful exercise for teaching a dog to go to a particular position such as a send away. It can be used for teaching jumping, to send the dog over the jump to the target and then back. Other exercises which use targeting are those where the dog's nose must be in a specific position, some people use target sticks for heeling. Eventually once the behavior is taught, the target stick will need to be faded, this means it must be gradually removed from the exercise.
A square of carpet can be used for sending the dog to a position, usually paired with a down command, and can then be used for the send out. The advantage of the carpet is that it can be made smaller and smaller so that it can be faded easily. You can also use other targets, a traffic cone, a piece of carpet, or a plastic lid, agility trainers often use colored plastic and eventually transparent plastic to teach their dogs to hit the contact points on obstacles.