To add a One-off Attachment the Invoice need to first be created and saved. Once you have saved the Invoice you can edit it and add one-off attachments.
In the Web Portal, go to CRM > Invoices > select the Edit Pen for the Invoice you would like to add the attachment to > Click on the Attachments tab > Add your Attachments > Save the Invoice. The attachments will appear on the second page of the Invoice PDF.
In the App, go to Accounts > Invoices > select the Invoice you want to add the Attachment to > Attachments tab > + symbol to add photo from device library or take a photo.
Please note: Attachments can be image files such as (PNG, GIF and JPG) can be attached into the PDF, while other attachments (PDF, EXCEL, CSV, DOC, DOCX) will be available to select as attachments stored in Resources when emailing.