How can I change payment to employee from monhly to biweekly?

Welcome to the QuickBooks Community, 131corp.
 

You can change your employee's pay schedule under Employment details in QuickBooks Online. I'll show you the steps below.

Before changing an employee's pay schedule, ensure you choose the correct next payday and the end of the next pay period to match the new pay schedule.

If you haven't already set up a pay schedule for your employee, here's how to create one:

1. Navigate to My apps, then Payroll and select the Employees tab.
2. Click on the employee's name you want to update.
3. In the Employment details section, click the Pencil icon to edit.
4. Under Pay schedule, select + Add pay schedule.
5. In the Pay frequency, choose Every other week, and set the Next payday and End of the next pay period.
6. Rename the Pay schedule name and hit Save.

After that, let's assign the Pay schedule you've created to your employee. Here's how:

1. Go to the Employees.
2. Select the one you want to update.
3. Under Employment details, select Edit.
4. In the Pay schedule, choose the one you created.
5. Hit Save.

You can also refer to this article for more information and guided steps about updating pay schedules: Set up and manage payroll schedules.

Feel encouraged to let us know in the comments below if you have any other concerns or questions about QuickBooks.