100% depends on where you’re going and how far journeys are.
For a small inner city area, a subway is great. For a larger urban area, a tram system. For intercity travel, trains. Out in a rural area, buses would be the way, although more remote locations would need government subsidies to be even remotely functional, and even then it may resemble on demand taxis rather than a scheduled bus service.
No single solution will get you all the way there.