If you are travelling to Sweden as a tourist, you will not require a visa for a period up to 90 days. Countries that do not require a visa include most of the the European Union and Latin America. Countries like the the USA, Canada, Australia and Mexico, however, do require a visa.
Living in Sweden requires you to obtain a residence permit from the regional government office. In general any stay that lasts longer than three months, or involving studying or working in Sweden, will require a residence and/or work permit.
Therefore, if you plan to live in Sweden for an extended period of time, a visa on its own may not cover you for this. You need to be clear whether you are applying for a visa or a residence permit.