You will receive a BSN "Burgerservicenummer" once you come to the Netherlands. You must Register at city hall to be able to receive a BSN number. Once registered to the municipality, Eindhoven will automatically provide you a BSN number. It is needed when dealing with Dutch authorities, such as Government organizations. As BSN can be needed in some simple situations, such as telling your GP reception that you have arrived for the appointment, it is handy to have it saved somewhere with easy access (such as your phone).
Eindhoven BSN page in English can be found here.