If you want to visit Sweden and you are not a citizen of the EU/EEA, you may need a visa. A visa gives you permission to enter and stay in Sweden for a short period of time. It is valid throughout the Schengen area, but you apply to the country that is the main destination for the journey.
Note that if you are planning to stay longer than 90 days, you need to apply for a visitor's permit. You must apply for the whole period initially, at the Consulate General. When signing your visa application, you undertake to leave the Schengen territory before the expiry of the visa. Therefore, stating that you plan to stay for maximum 90 days then apply to prolong the stay without special reasons, might lead to rejection of future visa application.
Some nationals are required to go through a mandatory prior consultation procedure during the assessment of the visa application. This is to check whether any Member States has any objection for issuing a uniform visa. The procedure takes up to 14 days. A comprehensive list of citizens subject to consultation is found in annex 16 to of the Visa Code. Click here for Annex 16.