What is the outermost layer of the earth's?

The Earth's outermost layer is called the crust.

It is relatively thin compared to the other layers of the Earth, with an average thickness of about 35 kilometers (22 miles) beneath continents and around 7 kilometers (4.3 miles) beneath oceans. The crust is composed of various types of rocks and is divided into several tectonic plates that float on the semi-fluid asthenosphere below. These plates are in constant motion, causing phenomena like earthquakes, volcanic activity, and the formation of mountains.