Easily record GPS coordinates in OpenStreetMap

I live in Argentina and use OpenStreetMap since the maps are really accurate in that area. I travel in a specific area with my Android smartphone using GPS. In that area mainly I like to save GPS coordinates in my map (my clients) and make notes to them. Additionally, I would like to add roads that are not recorded in OpenStreetMap yet, but that is not really necessary. Currently I use the OsmAnd app on my phone. It contains offline maps, which is important since I don't have any Internet connection out there. I can record favorites, but I can't really make many notes to them, like some kind of history of my visits. And I can't extend the map of unknown roads with that app. Is there a better way to achieve that? I would like to use the favorites to see where I have to make my visits next and what would be the best route for that.