If you want to email from InterFormNG2, then you can use this check list:
1.If you want to add an extra attachment to an email (apart from the usual PDF file), then you can define the attachment with any of the workflow components below (in the order that they should be attached) before the email is generated and sent. That can be done with these workflow components: From file to attachment, Payload to attachment, Payload to first attachment, Resource to attachment and URL to attachment followed by e.g. the normal email component, Create PDF email, Create EML with PDF.
2.You can also build up the email with these workflow components, if you e.g. wants to send emails without an attachment with the component, Send an HTML email.
3.If you want to create an email with a single attachment, which is not the usual PDF file, but e.g. an Excel spreadsheet, then you can consider a workflow, that first saves the original (XML or spooled file) payload with the component, Payload to named property, then set the attachment name and then generate the spreadsheet with the component, Create Excel document, then add the attachment with Payload to attachment and then retrieve the original XML payload again with the component, Named property to payload, before you use the Send an HTML email component.
4.If you want to collect e.g. PDF files with invoices from a folder, that are waiting to be sent to a customer as multiple attachments in a single email, then you should consider example 1, which is shown for the workflow component, List filesystem. There is also a suggestion for an add on in example 2. Direct file access is a prerequisite for this solution.
5.If file access is not an option and you still want to collect multiple PDF files found in a folder and add them as multiple attachments in a single email, then you can consider to save the files as resources e.g. in the other folder of the Library. Then you should consider the workflow component, List resources and build a workflow similar to what is shown in example 2.