Allow me to share some insights about importing payroll data in QuickBooks(QBO), hannah_churchill.

I understand how the feature you're looking for would be beneficial to your business so you'll be able to import the payroll details from QuickBooks. While the option is unavailable, you'll want to enter them through the prior payroll process or enter them using a journal entry. 

Once you've entered all the payroll data, you can create the next payroll of your employees. For detailed steps on recording prior payroll, I'm adding the article I recommend on this: Recording payroll transactions manually

You can try looking for third-party apps that import payroll data to QuickBooks. Simply click on Apps in the left navigation bar and search for something like transaction importer or data importer. To look for a third-party application on our App Center, you may visit this link: QuickBooks App Store.

I recommend checking this article to learn more about what data will be converted to QBO: Import Data Conversion to QuickBooks Online - Frequently Asked Questions.

I’m looking forward to the success of the conversion process in QuickBooks. As always, Community is continually open 24/7. You can post here If you have other questions in QuickBooks. Just click the reply button. Have a great day, and stay safe!