This question might look stupid but I wondered ifDo two computers connected on the same wifiWi-Fi have the same ipIP address (for example, my dad's computer and my computer, at home)?
answerAnswer: externally yes, within your network no
If so, how does the outside world distinguishes one computer with the other ? (e.gfor example, when a server wants to send us back some data)
answerAnswer: The outside world does not distinguish, it will communicate to/from your external ipIP address. The router's job is to distinguish. Each device on your wifiWi-Fi will have a unique local ipIP address.