get distance between two addresses

Hello !

I would like to know (with php) the distance in kilometer between two addresses with a car.
Is there an api available for this?

That requires a routing engine. There are several, and some have an api too. graphhopper.com is one, basing upon osm, but I cannot promise it will meet your requirements.

see https://wiki.openstreetmap.org/wiki/Routing for more routing engines based on OSM data.