Wires are used to designate the signal path in your circuit. You can drag a horizontal or vertical section of a wire by clicking-and-dragging the center of that section:
You may also configure wires by clicking on them with the right mouse button and choosing the routing method and color desired from the popup context menu.
More help with wires is available – see Working With… Wires in the main help system (Open the main help system by pressing F1).