To get a report of your customer sources click Reports in the left menu.
In the Other Reports section, click Customer Source.
Select the Date Range you would like to be on the report.
This will show the customers added during the date range chosen.
By default it will show Current Year to Date.
Select the Customers you would like on the report.
By default it will show All Customers (that were added in the date range selected.)Select the Customer Source.
By default it will show all Sources (for the customers and dates selected)Use the Export dropdown to download an Excel or CSV file, or Download / Print to download a PDF or print it. 
Here is how to add/edit a customer’s source:
Go to Customers > Customers.
Find the customer and click the pencil button.
In Customer Source, choose a source from the dropdown, or click the green + to add a new one.
This page saves automatically when you click outside of the field you updated. 