Hi,
For the login confirmation email which is sent when users register via the registration form of HikaShop, you can edit it via the menu System->Emails in the Business edition. You can also edit it in the folder media/com_hikashop/mail but not that you will loose it when you update if you edit the file. With the interface edition, it is done via an override so it won't happen.
For the login information and the change your password request emails of Joomla you would have to edit the joomla core files as they don't have such system. Here is some information about that:
forum.joomla.org/viewtopic.php?f=500&t=440226
There is also an extension which allows you to change the joomla emails:
extensions.joomla.org/extensions/contact...feedback/email/19516
