Data manager - Classification Fields purpose

Hi all,

I have a question regarding the Classification Fields from Data Manager. More precisely, what is the purpose of this classification and how can we use it in Studio?

Many thanks

Classification Fields

Data points which refer to a document as a whole. For instance, the Expense Type of a receipt (Food, Hotel, Airline, Transportation) or the Currency of an invoice (USD, EUR, JPY) would be examples of Classification fields.

When I loaded the default po schema in to data manager it had showed currency as classification field automatically…