Oral presentations are common, and mean that you present a task verbally. The length of a presentation and the number of people you present to will vary. Oral presentations are often compulsory and thus a form of examination. However, this varies depending on the examiner and assignment.
Seminars are a common form of both teaching and examination. The difference between lectures and seminars is that you are expected to work and be more active in seminars. A seminar can be regarded more detailed than a lecture, where you learn the basics. Seminars can have different formats. One could be that you are your classmates are divided into groups and have discussions.
Are you unsure about something? The study support unit at Södertörn University offers support before and during your education. For example, you can practice learning to speak in front of a group or your academic writing.