Please I want to find out if it is possible to carry my transactions and details (company files) from Manager to QuickBooks? I work with Manager but my boss has registered our company on quickbooks online per the advice of our auditors. So I want to migrate from Manager to QuickBooks.
There is no way
You would have to ask Quickbooks support what import facilities they have. If they have any I suspect actually doing it would involve employing someone with detailed computer data manipulation skills. And you deciding exactly what data transfer you are prepared to pay for (time or money).
As you need to import files in Quickbooks, I think you should ask them.