You may want to attach additional documents such as supporting e-invoices or credit notes. Use the AdditionalDocumentReference element to attach the file.

Elements

Element	Description
`Invoice/AdditionalDocumentReference/ID`	Specify an ID for the attachment.
`Invoice/AdditionalDocumentReference/DocumentDescription`	Specify a description.
`Invoice/AdditionalDocumentReference/Attachment/ EmbeddedDocumentBinaryObject [ mimeCode ]`	Specify the type of file. For example `mimeCode="application/pdf`
`Invoice/AdditionalDocumentReference/Attachment/ EmbeddedDocumentBinaryObject [ filename ]`	Specify the file name. For example `human_readable_original.pdf`
`Invoice/AdditionalDocumentReference/Attachment/ EmbeddedDocumentBinaryObject`	Specify the binary object that represents the attached file. For example `ZWNvc2lvIC0gY29ubmVjdGlvbnMgdGhhdCB3b3JrCg==`

Restrictions

You must create a group for each attachment.
The file formats differ for each country. Here is a selection:

Name	File Externsion	MIME Type
JPEG	`.jpg`	`image/jpg`
Protected Document Format (PDF)	`.pdf`	`application/pdf`
Microsoft Excel	`.xls`	- `application/excel` - `application/vnd.ms-excel` - `application/x-excel` - `application/x-msexcel` - `application/vnd.openxmlformats-officedocument.spreadsheetml.sheet`
Common Separated Values (CSV)	`.csv`	`text/csv`
Plain Text	`.txt`	`text/txt`

Country Specific Configurations

Example

<ubl:Invoice>
    <cac:AdditionalDocumentReference>
        <cbc:ID>human_readable_original.pdf</cbc:ID>
        <cbc:DocumentDescription>original invoice as sent by email</cbc:DocumentDescription>
        <cac:Attachment>
            <cbc:EmbeddedDocumentBinaryObject mimeCode="application/pdf" filename="human_readable_original.pdf">ZWNvc2lvIC0gY29ubmVjdGlvbnMgdGhhdCB3b3JrCg==</cbc:EmbeddedDocumentBinaryObject>
        </cac:Attachment>
    </cac:AdditionalDocumentReference>
</ubl:Invoice>