If your contacts are not receiving any files that you attach when you create a new ticket on their behalf, enable this setting in your New Ticket Auto-responder email notification.

• Navigate to Manage >> Notifications >> Contact Notifications >> New Ticket Auto-responder.
• Go to Templates, and click on the template you're going to add the option.
• Enable the checkbox next to Include attachments under Template options and hit Save.

With this in place, your contacts will now receive any files you attach when creating a new ticket on their behalf.