Hello there, John Lambert.

You can convert the IIF file to CSV as suggested by my colleagues. For your journal entries having split amounts, you can import the single transaction and split it after importing. For more details on how to split bank transactions, you can follow the steps under the Split transactions between multiple accounts section of this link: Categorise and match online bank transactions in QuickBooks Online.

You'll also want to search and get a third-party app in our Apps Center that will help you directly import your Journal Entries into QuickBooks Online. You can search something like import and a list of the related search will show. You can click each app one by one to get an overview of how it works. 

I'll be around if you have other questions. Take care and have a good one!