International non-exchange students apply to courses and programmes via universityadmissions.se. Exchange students have a separate process that is described here.
Universityadmissions.se also has information about how to apply, selection, entry requirements, documentation and important dates. Another useful website that describes the application process is https://studyinsweden.se/plan-your-studies/how-to-apply/
The dates for upcoming application periods are available at universityadmissions.se.