Last financial year have Unpaid invoice. Will be paid but with additional cost will be added (court)

I will guide you on how to properly record unpaid invoices along with any additional costs, @Benmetal.

Let's begin by creating a fee as a service item. This will allow you to add a fee with a detailed description to your invoices. Once we've created the item, we can move on to adding it to an unpaid invoice by editing it.

To create a service fee item, here's how:

1. Go to the Gear icon and select Products & Services.
2. Next, click on New and select Service.
3. In the Name field, you can enter the preferred name for the service fee, for example, "Solicitor and Court Costs".
4. Fill out the required fields and then click on Save and Close.

You can also utilize the Category dropdown to select the category that best describes the fee: Group products and services into different categories in QuickBooks Online.

To add the service fee to the unpaid invoice, here's how:

1. Go to the Sales tab and click on Invoices. 
2. Select the unpaid invoice you want to add a service fee to.
3. Click on Edit Invoice.
4. From the Product/Service dropdown, select the service fee you created.
5.  Enter the amount of the service fee in the Amount field.
6.  In the Message on Invoice section, add a note about the fee.
7. Select Save and Close.

If you have any further questions about managing invoices in QBO, please feel free to come back here in the thread. I would be happy to assist you.