If you want to visit Sweden for less than 90 days, you need a Schengen visa. If you want to visit for more than 90 days, you need a visitor's permit.
More information is available at visiting Sweden.
Sweden has diplomatic relations with almost all States in the world. It has embassies and consulates in around half of these. Sweden's foreign representation consists of approximately 100 missions abroad and 350 honorary consulates.