After making a correction to a document, DocuSign send file - but recipient does not receive an email saying envelope was corrected. How can I ensure they get an email that the change has been made?

You could select the "Resend" option on the envelope. If they are the next person in the envelope workflow that needs to take action they will be sent a notification email.

Remember in DocuSign each DocuSign User under their own DocuSign Account (if they have one) can set Notifications. So technically the DocuSign User controls if they receive different types of Notifications including those of a correction type. If they have taken the steps to disable notifications in their DocuSign Account they need to make sure they are able to manage envelopes within their DocuSign Inbox.