How can I create tickets with attachments using API?

You can use the following curl command : 

curl -v -u user@yourcompany.com:test -F "helpdesk_ticket[attachments][][resource]=@/path/to/attachment1.ext" -F "helpdesk_ticket[attachments][][resource]=@/path/to/attachment2.ext" -F "helpdesk_ticket[email]=example@example.com" -F "helpdesk_ticket[subject]=Ticket Title" -F "helpdesk_ticket[description]=this is a sample ticket" -X POST https://domain.freshservice.com/helpdesk/tickets.json

For more information, please click: https://api.freshservice.com/#create_ticket_with_attachment