I'm happy to see you here in the Community, @joan_ke.
You'll need to record your payroll transactions as a journal entries since QuickBooks Online Singapore doesn't have a payroll function inbuilt.
To do that:
Here's a link that you can check out that contains a sample scenario on how to enter payroll transactions in QBO: Recording payroll transactions manually
On the other hand, to view the payroll details that you've entered, you can pull up the Profit & Loss report. This displays data from the income and expenses of your account, including journal entries.
To learn more about the reports and data available in QBO, please see this article: Targets vs. Sources overview
If there's anything else you need about this or any QuickBooks related concerns, let me know. I'd be pleased to help. Have a great day!