You can use Google URL Scheme for navigation from location to location. The documentation is great, but you must validate if the google maps App exist on the user iPhone.
OPTION 1 :
Example :
If user have iOS 5 and older, use Google URL Scheme,
If user have iOS 6 and google maps installed, use Google URL Scheme
If user have iOS 6 and google maps not installed, use Apple maps URL scheme
Google URL Scheme documentation
Attention, when using Google URL Scheme, your application switch to Google Maps app.
OPTION 2 :
Is there any option to use the same but with google maps
Does it require app download or something like that?
Yes, Google Maps SDK for iOS