Press [Security].
Press [Signature].
Press [OK].
The certificate (device certificate) installed on this machine is used to attach signatures.
If a certificate has expired while transferring e-mail from the server to a destination, the destination might not be able to receive the e-mail. For details about a certificate, see "Protecting Communication Paths via a Device Certificate", Security Guide.
Note that the following can result if certain signature settings are specified by the administrator:
[Signature] does not appear. This is because you cannot apply signatures to scan files that are sent by e-mail.
You cannot change the [Signature] settings. This is because a signature is always applied to scan files that are sent by e-mail.