When you are finished with your studies and have defended your thesis, you should apply for your Master's degree diploma.

The application for the diploma is administrated at SU. Go to the web page and read more about how to apply for the diploma, https://www.su.se/english/education/qualifications-degrees/application-for-a-degree-certificate

If you are a 5-year student from KTH, you will also receive a "civilingenjör" degree upon application via this link: https://www.kth.se/en/student/studier/examen