First, you will need to log in to the Listserv Management website. Instructions for this can be found here: 

https://support.goarch.org/-/accessing-the-listserv-management-website

1) Once logged in, under List Management, click on "Subscriber Reports"

2) Under Report Format, choose "CSV Format" and click Update.

A comma separated version file will be created which can be used within Microsoft Excel, Google Sheets, Apple Numbers, or another program which reads CSV files.