When placing a component(symbol) on a wire, it will be put on the wire and junctions will be added at the connection points.
When placing a component on a wire with the Ctrl key pressed, it is possible to interrupt the wire with the component.
By interrupting wires, it is possible to place resistors and condensers, etc. without having to redraw the wire.
Placing Components on Wires
Placing Components on Wires with Ctrl Key
This can be done when newly placing, moving or placing components using Copy & Paste.