Why the Moon can be visible during the daytime

I saw the Moon in a bright blue afternoon sky and realized I still instinctively think of it as something that comes out at night. I know the Moon orbits Earth and reflects sunlight, but which part of its orbit makes it visible during daylight? Is the familiar full Moon mostly a nighttime sight because of its position opposite the Sun, while other phases appear in the day? A simple geometric explanation would be lovely.