Direct evidence for the interior of the Earth comes from measurements and samples that are taken directly from the Earth's interior. This can include things like rock samples from deep mines, or measurements of seismic waves that have traveled through the Earth.
One example of direct evidence is rock samples that have been brought to the surface by volcanic eruptions or other means. These samples can provide geologists with information about the composition and structure of the Earth's interior. For example, by studying the minerals in a rock sample, geologists can infer the temperatures and pressures that existed in the Earth's interior when the rock was formed.
Indirect evidence, on the other hand, is information that has been inferred from measurements or observations that are not taken directly from the Earth's interior. One example of indirect evidence is the study of seismic waves, which are waves of energy that travel through the Earth's interior in response to earthquakes or other disturbances. By measuring the speed at which these seismic waves travel through the Earth, geologists can infer the density and composition of the materials that make up the Earth's interior.