Hur kan jag förlänga min prenumeration

Please be aware that only English and Deutsch languages are supported in this Community, and English language needs to be used in this part of the forums. 

I have done a quick translation of your question, which seems to be:

"Who should I contact if I want to extend my subscription"

This depends on which F-Secure product you're using, for example, F-Secure SAFE is renewed through the SAFE Portal, but there may be different methods for different products.  If you could give us a few more details, we may be able to help better.