Hello Yessen,
First: where is the information stored? Take a user ID, go to table USR21, get the address number, then go to table ADCP and enter the address number and get your information, like department. Eventually there is even a function module or a BOL business object for it but I don't know any.
Second: How to display in WebUI? Take an existing view (like employee-user-relation) or create a new view (which is slightly more complicated but explained in other threads). Then create either a value node or a value attribute to a model node and fill the information in the GET-method of your field.
Summary: All this is not very complicated.
Best regards,
Thomas Wagner