We can see the moon during the day, for the same reason we see the moon during the night. The surface of the moon is the reflection of the sunlight in your eyes. But why don't we see stars in the day?
"The stars are not as bright and clear as the blue sky during the day, but the moon is roughly the same, as is clear in the flash of the sunlight and of the sky during the day, and that is the reason why we see the moon during the day, but it is not in the stars, during the day," O'meara said.
However, we do not see the moon the moon the whole of the period of time during the day, and that's because it is the place where the moon would be in heaven.