From any page in Ketryx, on the right sidebar, click on "Organization" and then select "Members"

From the members page, click on the icon on the top far right side, which brings your to the members page: https://app.ketryx.com/org/members

In the icons menu, select either "Download data as CSV" or "Download data as Excel" and open in the application of your choice. 

Using this exported spreadsheet, you can also determine the number of users in your organization. 

From the Groups page (https://app.ketryx.com/org/groups), you can perform the same actions to download a CSV or Excel with the group membership.