Hi, welcome to Android Forums.
From your description I think you are referring to the blue navigation icon which was associated with Google maps version 6. For a lot of android users this icon disappeared when Google updated maps to version 7, although some, like me, have somehow retained it.
However, as long as you have maps version 7 on your device you will still have Google navigation available to you. It is accessed from within the maps app.
When you open maps you will see a search bar at the top with an icon resembling a road junction with an arrow head pointing to the right, tapping that will take you into navigation, or you can either enter a destination into the text area or, if you tap the empty text area you can view recent destinations etc.
It is also possible to go into navigation straight from a google search for a destination where you see the 'road junction/arrow head' icon.
If you have lost the maps app you can download it from Play Store.
Some people have gone back to version 6 but that is down to personal choice. If you would like help to do that or more help with version 7, I would suggest that you consider registering as a member then you can benefit from a full dialogue on this and other issues.
You can register here :-
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