A Code Signing certificate allows developers to sign software digitally, which verifies the integrity of the software and ensures that it has not been tampered with since being signed. Self-Signed certificates could be used but aren't typically trusted by users' operating systems or browsers by default, thereby potentially raising security warnings. An Email certificate is used for securing email communication and ensuring the authenticity of the sender, not for software integrity. A Root certificate is at the top of a certificate chain and signs other certificates rather than being directly used to sign software.