The script is available for download from https://gallery.technet.microsoft.com//How-to-create-General-ee3ae489. You can also use Microsoft Script Browser for Windows PowerShell ISE to download the sample with one button click from within your scripting environment.
This script will create a report in CSV for Mailboxes Detail.
This script is to help Exchange Admins to create a report for Mailboxes via PowerShell.
You can find more All-In-One Script Framework script samples at https://aka.ms/onescriptingallery