Amy informs her employees that they can offer any constructive criticism regarding her leadership style by placing anonymous notes in her mailbox. this is an example of

This is an example of "upward communication."

Upward Communication is the procedure of data spilling out of the lower levels of a chain of command to the upper levels. This sort of correspondence is winding up more prevalent in associations as conventional types of correspondence are ending up less prominent. The more customary association composes, for example, a progression, places individuals into discrete ranks. Upward Communication encourages workers to express their necessities, thoughts, and feelings. Upward correspondence is broadly utilized as a component of whistleblowing strategy in numerous substantial associations.