How to I close old payroll file? This year I have merged payroll in the same file where I do the books so need to close the old payroll only file?

Hi electrohm, thanks for reaching out to the QuickBooks Community

In QuickBooks Online Standard Payroll, there isn't an option to close the payroll. Instead, you would simply cancel the payroll subscription (in the Account & settings, go to Billing & subscriptions and in the Payroll section, select Cancel). 

If you're closing the PAYE scheme, you'll need to notify HMRC through their Basic PAYE Tool. The tool is an online form that allows you to close your PAYE scheme. You'll need to provide your PAYE reference number, the date you want the scheme to be closed, and the reason for closing the scheme. Once you've submitted the form, HMRC will process your request and send you a confirmation email.

Thanks again for reaching Intuit QuickBooks Community for support. If you have any further queries, please don't hesitate to get back in touch.