I'd like to add more information to what Fiat Lux - ASIA added. You can import your data into your QuickBooks Online account. For those details that we're unable to import, you can enter them manually. Here's how:
Go to the Gear icon.
Click Import data.
Select the data you want to import first.
Follow the onscreen instructions until you've successfully imported the data.
If you're using other third-party apps in importing your database, you can contact them directly. Our Intuit Developers can also help you through it.
You can check out these references on other ways to import data: