I am developing an app in which I need to download OSM map and show map in offline mode. Can you please help me where I can get the tutorial for it or any way to download vector data. I have visited maps.me also but it is not much helpful.
The most authorative vector form of OSM is the .osm format, which is returned by the API and by various tools like Overpass. The API is intended for getting the absolute latest version for a small area, with the intent to modify it, and overpass is intended to allow bulk requests with data that is not completely current.