I found that when you zoom into a ticket, on the right side, you will had a column that displaying:

Customer Info:

Firstname:

Lastname:

Username:

Email:

 

This column also same as the one when you click on "Phone Ticket" on top of the navigation bar. When you type in the customer's name in the From: field, and clicked search, you get the information displayed on the right side:

Customer Info:

 

I also did found that this column template is located in:

/opt/otrs/Kernel/Output/HTML/Standard/AgentCustomerTableView.tpl

 

I wished to add the `comment` field whereby this field is original held in otrs. Located in table:

customer_company.

Field: `comments`.

 

Of course, this customer must match with the company with the same customerID. The output will be something like: