You should choose whether the signature should be official or commercial according to the file type. Signature of official documents: instructions on how to examine, sign and approve the issuance of official documents before they are issued. In general, the handling notice shall be filed together with the official documents for reference. Business visa mainly refers to the on-the-spot investigation or negotiation of relevant personnel who go to the destination country for investment, trade, conferences, exhibitions and labor services for official or personal reasons. So choose business sign or official document sign according to the file type.