You can download the map data for a specific area and edit the map. After editing, you can upload it directly to the OSM servers.
Any accidental change can be undone and all changes are listed for review before upload. Tag-autocompletion, JOSM compatible presets, links to the translated map-features pages and even autocompleting nearby street names help to find the right tags to use.
More information and documentation can be found on vespucci.io and in the on-device help.