EU/EEA citizens do not need visa.
Non EU/EEA citizens, who intend to stay in Norway is less than 90 days do not need to apply for a residence permit, however depending on your nationality, a visitor's visa might be needed to enter Norway. Check if this applies to you, and how to proceed on the webpage: want to apply to visit Norway (udi.no) of the Norwegian Directorate of Immigration (UDI).
An application for a visitor's visa must be supported by a written invitation by your host unit at the University of Stavanger. Please contact the host directly.