Is it possible to upload client information in Quickbooks online including the custom fields? The CSV template only shows Quickbooks default fields.

You can use a 3rd party tool to import data with up to 3 custom fields.

https://get.transactionpro.com/qbo

Hi there, Deo.

I know how important it is to import your client information and the custom fields to QuickBooks Online.

While this option is currently unavailable in QuickBooks Online, I recommend sending feedback directly to our product engineers.

Here's how:

1. Select the Gear icon and choose Feedback.
2. Fill in your suggestions in the Feedback field.
3. Select Next to send it.

We'll take note of your feedback about importing the custom fields.

You can also use a third-party app to integrate with QuickBooks Online to import your custom fields, as @SIAB has stated.

Moreover, you can also consider exporting your lists and other data from QuickBooks Online.

Feel free to leave a reply if you have further concerns you may have besides importing custom fields into QuickBooks Online. I'm always here to assist you anytime.