Point-to-Point
When nodes(Sender & Receiver) are directly connected, Data transmission is done through a guided medium for wired network and through unguided medium for wireless medium.
Multi-Point
A number of nodes are directly connected through a common medium in a linear fashion. It is like a one device to many device data transmission mode.
Concept of multi-point transmission works on either Time sharing connection or Spatially shared connection. In Time sharing connection, each node is offered a separate slot of time to communicate. But in Spatially shared connection, all the nodes can communicate simultaneously at a time.