Great question.
Data conversion is for moving tax data files from another program, like TurboTax, to ProConnect. https://proconnect.intuit.com/community/convert-data-files/help/proconnect-tax-online-conversion-inf...
Batch Actions | Transfer Prior Year Return Data moves ProConnect tax returns from one year to the next.
https://proconnect.intuit.com/community/customer-lists/help/how-do-i-proforma-or-roll-over-my-prior-...
