Hello,
HikaMarket do display the plugin fields are they are describe in the plugin configuration variable.
"Banktransfer" to have the field "information" as "big-textarea" to let the user (backend/front-end) use a big textarea to enter its raw content.
HikaMarket does support various kind of fields, such as "input", "boolean", "checkbox", "price", "textarea"... but also "wysiwyg".
That kind of field is use for the plugin description.
If you change the HikaShop bank transfer plugin to use "wysiwyg" instead of "big-textarea", you should have something closer to what you want.
BUT !
1 - Save the in front-end will not get the "wysiwyg" data due to a constraint of the Joomla wysiwyg editors. (I made a patch for that, not available yet)
2 - because that plugin is a core plugin, the best is to not edit it but to duplicate it ; otherwise you will loose your modification at the next update.
3 - HikaShop backend do not handle "wysiwyg" type, thus you won't be able to see the field value in the backend and will generate some unwanted side-effect if you try to save it.
So, the best solution would be to add the support in the HikaShop core for "wysiwyg" fields.
Thanks to that, HIkaShop will be able to handle that new type, like HikaMarket does.
Regards,