Why is documentation important?

In simple terms, documentation is important, because you need to store and preserve data for futuristic reference Documentation is needed in some niche industries like hospitals, security service companies etc My2 cents

to preserve data and to audit data these are the basic knowledge about why documentation is important and to walk far in it there is also methods and rules in which documentation is applied,also there is cost which is an important factor in documentation.
Bottom line documentation is not important but mandatory in any successful corporation.
A.Alsaedi

Documentation is important so the facts of the case can be preserved.
Documentation can also make sure that policy was followed and understood throughout a disciplinary process

Document is a record for reference of each and every activity in a Business its  very useful to maintain in such a way to handle to a record event.