I can't import presets in Lightroom CC (XMP-Files), which I have developed in Lightoom Classic. I miss Option the Menue.
Have you clicked on the three dots?
When I click on the dots in saw this option
That is odd. As you can see from my screenshot, the three dots light up when you click on them. And the box that appears has a small triangle part pointing at the dots, so you can see that's where the dialog originates. I miss both in your screenshot.
What I do see however is a plus icon on the left of the three dots, which is probably the button for creating a new preset. That is a menu item in my version. This makes me believe that you are using an older version of Lightroom that perhaps did not support importing presets yet. Go to Help - System Info and check the version number. What does it say?
I use the Web-Version of Lightroom. Where could I find the Version number?
The Problem is solved
Right! The web version of Lightroom does not support importing presets.