I never figured out how to easily move windows on macOS.
How I know why; it's disabled by default and you also need to hold down `Ctrl`.
Personally I use Spectacle [0] and a few handy shortcuts to move and resize windows. For me, it's just enough customization without going over the board with scripting a window manager from scratch. As I just discovered, Spectacle is no longer actively maintained, but it still works just fine. The recommended alternative from their readme is Rectangle [1].