Downloads are provided in PBF format, which is interoperable with most tooling, such as:
- JOSM for editing
- osm2pgsql and imposm for lossy conversion to PostgreSQL tables
- OpenTripPlanner, Valhalla, OSRM for routing
- Pelias and Photon for geocoding
- Osmium and Osmosis for general processing
Try Geofabrik Downloads if you need less frequently updated data clipped to administrative boundaries.