Shared folders don't appear in the other person's finder

Hi Community,

I shared a folder that is located in my iCloud Drive.

The person I shared it with, can access the folder via their own iCloud.

She can also edit and read the files in the folder as it should be.

The problem:

She can not access the folder via her own finder on her mac.

She needs to go to the webpage all the time.

How can we add the shared folder to her finder?

Thanks for your help!