Latitude and the magnetic/map north conversion can be found on many maps --you can also add that to your map. Azimuth is shot with a compass --aim compass and face the target and where the needle points is your azimuth. That azimuth must then be converted --add or subtract a sum based on your latitude; the higher north of equator you are the more radical the change.
Also, many maps will have the latitude/longitude for a particular map on the map, generally near the magnetic north conversion you'll need for shooting azimuth.
I'm referring to military maps and maps made like those, road maps and cheaper maps and such may not have as much info. In that case, you can find it online and just update your map with the appropriate data you need on it.