How can I save a map (not PDF) on my phone ?

Hi,
I am mostly interested in using my phone OFFLINE so I try to save some documents on the intern memory. I was able to find the subway map as a PDF, which I could save easily. But there is another map (bike share map) that does not seem to exist as a PDF that I would like to save on the phone. I found the MAP (interactive map format), I found and saved the APP, but I can t find the way to save the map on the phone in rder to access it OFFLINE.

Is it possible?

Thank you so much!