Hello Tilges, 

thank you very much for your reply. 

Notes is a core feature of the OpenStreetMap.org website. It enables you to add a comment on the map to assist others in mapping/editing OpenStreetMap. Notes do not have a direct impact on the data in the project. 

If you want to capture or modify new data, I recommend the following website: https://wiki.openstreetmap.org/wiki/Beginners%27_guide

Thanks & Best regards.