Citizens from Nordic countries do not need a visa to visit Sweden. Sweden takes part in the Schengen cooperation. If you already have a valid visa issued by a Schengen country, it is usually valid also for visits to Sweden
In exceptional cases, the visa may only be valid for entry into the issuing country or only for certain countries. Thus, you may need to apply for a visa. Within the Schengen area this service is offered at the embassy in Athens, Berlin, Madrid, Paris and Rome.
Visit the relevant Swedish embassy website for more practical information.
The Swedish Embassy in Reykjavik does not handle visa applications.