The placeholder property provides a short hint describing the expected value of a field. The hint will be displayed in the input field before the user enters a value.
For example, a sample value or a short description of the expected format
This property provides guidance to an author for the expected content that the field should contain. Where possible include guidelines for every field in your content type. This will help authors know what content you want added to a field.
The content guidelines are shown below the field editor when an author is populating the field.
This property allows you to change the size of the rendered field editor when creating an entry. It usually changes the height of the editor to allow more content to be seen at the same time without needing to scroll.