In order to add the ability to view the full ticket correspondence on each ticket a variable to the signature needs to be added, please follow these instructions in order to achieve this goal.
1. Navigate to Settings > Ticketing > Signatures, and click to edit the signatures being used by your agents.
2. Add the " %fullquote% " variable to the footer of the signature.
This will make sure that on each reply that it sent to the end user, the ticket will include the history correspondence of that same ticket.
Please see image below as an example.