The age of the earth is 454 crore years. During this time, the earth has undergone unimaginable changes. Many times the earth shone on its face. For example, 300 million years ago, there were no oceans on earth today, only oceans. And a single continent. At that time, there was only the super continent of Pangea.
Later, before this super continent erupted, many continents separated them into oceans. The splits sometimes crashed into one another and formed into mountains. That is how the Himalayas came to be.
The journey of the continents still continues. Over time, they may come together and split again.