An official acknowledgment that a letter or package has been posted

डाक प्रमाणपत्र के तहत

English Usage: He sent the documents under certificate of posting to ensure they were received.

Hindi Usage: उसने यह सुनिश्चित करने के लिए दस्तावेज़ डाक प्रमाणपत्र के तहत भेजे।