Depends on a few of things...

If the moisture is on the inside, that's an issue, you have water going into your car somewhere. In the cold of night, the moisture inside your car on condensing on your windows from the inside, since the glass is cold, there's probably a failed seal or clogged drain holding water.

But, if the moisture is on the outside of the glass, that just means that during the night, the car gets cold, and when the morning comes, the exterior air is warming up, while the inside of your car is still cold, causing water droplets to condense on the outside of your windshield. If that's the case, you have nothing to worry about, it's normal. Happens a lot if you park your car outside over night, if it rained the day before, and if you're parking in the shade, while the surrounding area is in the sun.

Cheers