Use the importer to upload classifications into reporting and analytics. You can also export the data for updating prior to an import.
Admin > Classification Importer
The data that you import using the import tool must be in a specific format. Adobe provides you with the option to download a data template with all the proper header details in a tab-delimited data file. You can add your new data to this template and then import the data file in the browser, using FTP.
See Common Classifications Upload Issues: Knowledge Base article that describes issues arising from incorrect file formats and file contents.