What happened to the outer surface of the moon when the moon cooled and a crust formed over the molten interior?

When the moon cooled and a crust formed over its molten interior, the outer surface solidified, leading to the creation of a rugged landscape characterized by impact craters, lava plains, and highlands. As the molten material solidified, volcanic activity contributed to the formation of the Maria, the large basaltic plains visible on the moon's surface. This process resulted in a geologically diverse landscape, while subsequent impacts from meteoroids shaped its current appearance. Over time, the lack of atmosphere and weathering preserved these features, making the moon's surface relatively unchanged for billions of years.