What fits in a Data Description Report/ Data Exploration Report?
Generally speaking each data set may have different structure and may relate to different business aspects.
Because of that I think its hard generalizing the description/exploration steps.

Yet, these are my two cents:

Data description:
  * Data sources - how was data created, generated, collected.
  * Data shape - number of rows, columns.
  * Data types(per each column) - numeric, strings, other..
  * Missing values - how much, where, why?
  * Time frames - if relevant.
  * Entities(geographical, markets, population segments, devices) - what identifies a row in the data(if applicable).  

Data exploration:
* Counts per entity(grouping keys).
* Categorical variables breakdown.
* Values ranges distributions.
* Simple correlations.
* Story telling(visualizations that depict key aspects in the data&lt;>business realm).
* Missing data deep dive.