The documents that should be maintained those are purchasing order, sale receipt, cash or credit sale document include the sale condition with customer or contract papers. The information of customer such as address telephone number, discount account number or credit term condition are very importance that we also have to maintain because it is controlled by law to keep customer information.
In addition, information about customer complain, customer feedback should be maintained to be organization source to improve the defect and we can use this information to fix the problem that may occur in the future
Moreover, employee information or staff information about their background, salary, leave record, bonus or other payment should be keep in secret as well because this is a sensitive issue may effect to their feeling.
There are several ways to keep these information some we should keep by hard copy such as contract or law document because they have the signature of involve person. In other way, it is easier to keep document by staff copy such as a file or sending an email, we have technology like interest and intranet we can share our information on organization server so every staff can upload and download file immediately.