I accidently ran payroll for July instead of June of this year. how can I change the date on my payroll checks

You can't be able to edit the date. However, you can delete and recreate the paycheck, Jacque. I know how to do this. Let me provide help to achieve your goal.

If you have created a payroll check with a July date, it has not been processed yet. To resolve this, I recommend deleting the created paycheck and recreating it for June. Here are the steps to delete the paycheck:
 

1. In Payroll, go to Employees.
2. Click Paycheck list.
3. Decide what paycheck you want to delete. Go to the dropdown arrow, then hit Delete.
4. To confirm, tap Yes.

Additionally, I've included a reference link for you to learn more about managing your employee's pay history and company totals in QuickBooks Online Payroll: Add pay history to QuickBooks Online Payroll.

Please know that we're always here to help you with any queries. If you need further assistance, revisit us here in the Community space. Take care!