The package is not yet deployed to CRAN, but you can install the development version directly from GitHub.
By default the free public services at <api.openrouteservice.org> would be used. A local or a hosted instance might be preferable in order to perform larger unlimited requests. The default plan for the public service is 500 requests per day @40 requests per minute. See openrouteservice.org for more detailed information.
Take a look at the package website and checkout the introduction vignette.