Not recommended to show ticket number
Sorry, it is strongly not recommended if you show the ticket number on the next page after client open the new ticket, just like Peter Rotich said in one of his topics somewhere in this forum. I remember that is one of security issues in the system.
Please try to learn about email system and mail server in order to implement email-system in your place/company. I think e-mail is a mandatory thing in osTicket System.
Cheers!
Best regards,
Masino Sinaga