Classification is the process of evaluation and analysis of the data considering your sector, interests, or competitors on social media. Listen - You need to classify each of the contents in the Classification/Editing screen so that you can get some detailed reports, which include the graph that is created in accordance with the classification in the Reports page.
All the classification info will be available in your exported data too and it enables you to follow a detailed reporting process after the classification procedure.
There is a 3+1 structure on the classification and it includes Sentiment, Category, Label, and Tag selections. While the first three of these parts are selection-based option; the Tag part is a free-text.
For further information on the classification process, you might be interested in our other articles: What is Sentiment?