Write MIME activity
During run time the Write MIME activity constructs a MIME header and the body of the message from multiple attachments contained in the parts XML input parameter and optionally the mimeheader input parameter, as shown in the figure below.
For example, an orchestration could contain a Write MIME activity,
that during run time constructs a MIME header and a body of a message
and places the result in two orchestration variables. The orchestration
then invokes a Send Email activity that takes these two orchestration
variables as input and builds a mail message and then sends that mail
message to the specified SMTP endpoint. 
The steps for adding and configuring a Write MIME activity in an orchestration are described in: Adding a Write MIME activity to an orchestration.
