Trying to find out why I am charged 75kr every month on my Apple account?

This is primarily a user-to-user support forum; other Apple users like you. We don't have access to information about charges to your account. Apple has a support article about charges — see each of the steps in the following instructions. They include information on contacting Apple Support if the other steps don't help. See: If you see 'apple.com/bill' on your billing statement - Apple Support

If you have upgraded iCloud+ plan, once your request for iCloud+ plan has been activated, you should receive an invoice in your email box.

Check -> Go to -> Settings -> your name -> iCloud -> if you see 50 GB (or 200 GB or 2 TB) then you have an iCloud subscription.

If you have an iCloud+ plan subscription, you will receive a monthly bill from Apple, check your email box.

You pay monthly for iCloud storage.

See the following Apple articles:

iCloud+ plans and pricing -> iCloud+ plans and pricing - Apple Support

How to use iCloud on iPhone -> How to use iCloud on iPhone – Apple Support (UK)