Hi,
For the email logs, in the Hikashop Email History Plugin settings, that you can edit via the joomla plugins manager, you can set the parameter "Number of days" to define a retaining period for the log and the rest will be automatic.
For orders, there is no such mechanism as in most case, you want to keep everything.
But yes, you could create a mass action with a trigger "every month", a filter on the "order_modified" column with a condition < {time}-47340000 and an action delete the elements.
Note that in that case, you also need to configure your cron task:
www.hikashop.com/support/documentation/5...ashop-cron-task.html