Before you go to the Danish Diplomatic Mission to apply for a visa, you must have an invitation called VF2 completed by International Staff Office (ISO) at SDU.
You also have to get an official invitation letter signed by the host (the person that invites you to SDU), as this is something the Danish Diplomatic Missions wants to see because they compare it with the VF2-invitation.
If you have got any questions about the short-term visa application, you are welcome to contact the International Staff Office at iso@sdu.dk.