Unique order prefix for specific customer

Hi,

You will need to create a custom field of the table "user" and of the type "text" with the columna name "user_prefix". Don't display it on the frontend.
Then, you can create a custom field of the table "order" and of the type "text" with the column name "order_prefix". Just don't display it on the frontend and the emails, etc with the settings of the custom field.
In your special user settings, in HikaShop, you can enter the prefix you want in that custom field.
Then, you can use a mass action with:
- a trigger "after an order is created"
- an action "update the values" on the column order_prefix with the mode "operation" and the value: user.user_prefix

Then, in the "invoice number format" setting of the HikaShop configuration, you can use the tag {order_prefix} so that it will use the prefix when generating the number.