+.TP 13
+.I SENDMAIL_ARGS
+Set arguments to pass to /usr/sbin/sendmail. This can be useful to set
+credentials in order to authenticate to an smtp server when using ssmtp
+for example.
+
+.SH FILES
+The behavior of
+.B gpg-mailkeys
+can be updated through some files available in the user home directory.
+
+Thus,
+.B ~/.gpg-mailkeysrc
+allows the user to overwrite the default value for the above environment
+variables, and any text in
+.B ~/.signature
+will be appended to the end of the body text of the message.
+