Why does the moon appear in the daytime?

Because the sun shines at it

We can see the moon during the day for the same reason we see the moon at night. The surface of the moon is reflecting the sun's light into our eyes. "When we see the moon during the day it's because the moon is in the right spot in the sky and it's reflecting enough light to be as bright, or brighter, than the sky. The moon is visible in daylight nearly every day, the exceptions being close to new moon, when the moon is too close to the sun to be visible, and close to full moon when it is only visible at night.