I'm here to help you with adding bank transactions to show as an expense on the register in QuickBooks Online.
If you add the transactions from online banking into QuickBooks, it will show as an expense in the register. However, if you add the transactions and match it with any check or add a check number it will show as check in the register.
I have found out that the transactions imported form my bank are somehow marked as checks so when added to the registry they are imported as checks and not expenses as I would like. There's no way to change that apparently. The workaround I found is to create a rule that looks for specific keywords (e.g. "POS Transaction" in the bank text) and hence assign the expenses transaction type.