+.B \-headerfield
+.I name:value
+switch adds a header field with the specified name and value to the
+message. (The
+.I value
+is called the
+.I field body
+in RFC 2822, but that's too easily confused with the message body.)
+There need not be a space after the colon that separates the
+name and value in the argument to this switch. It is usually best to
+enclose the argument in quotes to protect it from the shell. The
+.B \-headerfield
+switch may be given multiple times to add multiple header fields,
+for example,
+.PP
+.RS 5
+.nf
+mhmail -from sender@example.com \\
+-headerfield 'MIME-Version:1.0' \\
+-headerfield 'Content-Type:text/plain; charset=utf-8' \\
+-headerfield 'Content-Transfer-Encoding:8bit' \\
+recipient@example.com
+.fi
+.RE
+.PP
+Note about this example: the
+.B \-attach
+switch causes
+.I MIME-Version
+and
+.I Content-Type
+headers to be added to the message.
+.PP
+The