If you are looking to convert any forum topic to tickets, so that you could reply directly to customers, you could use the option "Auto-Convert Topics to Tickets" inside the Forum folders section.
Once this is enabled, all new topics created in the respective forum would be automatically converted and created as a new ticket. This ticket would also contain a link to the corresponding Forum Topic. You could reply to these tickets and the reply would be sent to the customer as an email. While replying, you would also have the option to "Post reply in linked forum". When this option is turned on, the reply would be appended to the Forum Topic.