It is needed to be written...?

[SunMoon]

I am updating a document and I would write something like this:

It is needed to be written down.

I want to mean that there is a rule that anyone knows but it is not written anywhere, so it is needed to be written.

???

[2006]

I am updating a document and I would write something like this:

It is needed to be written down.

I want to mean that there is a rule that anyone knows but it is not written anywhere, so it is needed to be written.

???

It needs to be written (down).