Request to have directions link that goes to google map

This is not Feature Request, but rather a Support Request.
It should be you (and not the module) to be able to add an accessory field (to the entity you are providing with Geofield and then mapping with this module) that generates/render an automatic link to GoogleMaps pointing to that Address or Lat/Lon point of interest,
and then you could/should expose it in the Marker Infowindow or the Entity View page itself.

For instance for the Coliseum in Rome you should be able to generate automatic Google Maps link, both based on the address or the Lat/Lon pair:
https://www.google.com/maps/place/Piazza+del+Colosseo,+1,+00184+Roma+RM

https://www.google.com/maps/place/Piazza+del+Colosseo,+1,+00184+Roma+RM
https://www.google.com/maps/place//@41.8902102,12.489656,17z/

Automatically closed - issue fixed for 2 weeks with no activity.