What is the source document of depreciation?

The source document of depreciation is typically the asset's acquisition invoice or purchase order, which provides details about the asset's cost, useful life, and method of depreciation. This document serves as the basis for calculating depreciation expenses over time, ensuring that the asset's value is systematically allocated in financial statements. Additionally, any relevant supporting documentation, such as maintenance records or appraisals, may also be considered in the depreciation process.