Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. Any such information should be easy to search, focused on the user's task, list concrete steps to be carried out, and not be too large.
Jakob NielsenUsability rules the web. Simply stated, if the customer can't find a product, then he or she will not buy it.
Jakob NielsenUsers spend most of their time on other sites. This means that users prefer your site to work the same way as all the other sites they already know.
Jakob Nielsen