It is possible to attach voucher files to partial invoices. What this does is, it includes the file attached to the creditor invoice, be it a receipt, account statement or whatever else you might have attached.
To attach a voucher, it must be one of the approved expenses that you selected on the Partial Invoice tab:
See the full guide on partial invoices if in doubt.
There are three different methods for attaching vouchers. They are detailed here:
Include vouchers in the invoice document
This function embeds each attachment within the pdf file itself, and they can then be accessed through the attachment function in Adobe Acrobat.
A line appears at the end of the invoice, that informs the reader to open it in the acrobat to see attachments.
Attach each voucher when sending an invoice email
This function attaches each individual attachment to the invoice email when it is generated with the email function rather than print to pdf.
Attach vouchers in one file when sending an invoice email
This function uses the WorkBook email like before, but collects all the attachments into a single zip file.