I do not want to import my RAW photos in LrC to DNG format. Were can I deacivate this before importing. Thank you for your help.
You cannot de-activate the feature in Lightroom Classic. You simply need to avoid clicking on it.
As outlined, you have the option to NOT convert to DNG. Of course, we don't know what camera you're using and if it's native raw format is DNG, well then you have to import DNG.
Look at the top middle of the import dialog. You have selected 'Copy as DNG'. Change this to 'Copy'.