First we go to Finance > Generate Vouchers.
Type student’s name whom you want to search.
Student’s fee history will appear in a form of grid.
Select single fee month and click in Fix as shown in figure.

A type of form will appear.
Here you will see a Paid amount is 0 and Balance amount.

Copy balance amount in a Paid section and balance become 0.
As shown in figure

As you see the status of student have been paid.
This is because of balance fixing issue.