To add a one off Attachment the Quotes need to first be created and saved. Once you have saved the Quote you can edit it and add one off attachments.

Web Portal > Accounts > Quotes > edit the quote that you would like to add the attachment to > add your attachments > Save. The attachments will appear on the second page of the quote PDF. 

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.

Adding an attachment through the Web Portal video below;

Adding an attachment through the App video below;