After running payroll and the online submission, how should I post the payment of PAYE / NIC to HMRC in QBO?

Hello there, Janc58.

In QuickBooks Online, after you run payroll, the payment will be posted to the liability account. To pay the liability, you would simply make an expense to offset the amount.

I've got this article for the detailed steps: How to enter, edit, or delete expenses.

Feel free to get in touch with us if you have other questions related to this. Thanks.