Paper materials are generally required to be signed by hand, and it is not recommended to make the electronic version in front or stamped, because once the file (often changing, one person says one thing) becomes invalid, a lot of materials will be redone. As for who signed it, it depends on who is convenient, even if it is signed on behalf of it. Try to ensure that one person's handwriting is consistent, and don't let people see at a glance that many positions are signed by one person. It would be safest if I signed it myself.