You may have a variety of different Team Members who wish to see when the Invoice is paid. When the Invoice is sent to a Customer, only the sender will receive a notification when it has been paid.
However, all Team Members will be able to see that an Invoice has been paid. In order to check, please follow the steps below.
Go to "Invoices" on the left hand side.
Check the "Status" column to see if the Invoice is "Paid" or "Unpaid."
You can use the quick filter at the top of the Invoices panel that says "Paid Today" to filter all Invoices that were paid in a given day