How do I transfer data from one QuickBooks account to the other?

You can use a migration tool.

https://get.transactionpro.com/qbo

I can guide you about moving your data from QuickBooks Online (QBO) to another, timemaestrosg.

When transferring data, we can move your lists (customers, vendors, and others). You can do so by exporting them to an Excel file. Here’s how:

1. Select the Settings ⚙ icon from the toolbar.
2. Under Tools, select Export Data.
3. On the Reports tab, set the date range.
4. Add or remove items from the Reports and Lists tabs by toggling the slider.
5. Select Export to Excel.

You can also check out this article for other steps you can perform to get the other type of transactions: Export data, reports, lists, and more from QuickBooks Online.

Once done, you can import them to the other company file where you want them to add. Please go to this article and refer to Step 2: Import your lists to QuickBooks Online: Move your lists to QuickBooks Online.

Another way around, you can look for a third-party application that allows you to migrate your data from one another.

Furthermore, I added this resource to run a report in QBO. This will give you insights to check if all transactions are moved successfully.

Feel free to reply if you need further assistance with migrating data. The Community always got your back. Have a good one!