It is possible to request that each of the envelope’s recipients add one or more attachments: the recipient can attach one or more PDF documents to the envelope (any attachments uploaded in different formats will be automatically converted to PDF as part of the process); each individually attached document can weigh a maximum of 3 MB.
For more information on signer-uploaded attachments, see:
https://confluence.namirial.com/display/eSign/User+Guide#UserGuide-FormFields