You can delete an invoice in the following manner:

Invoices List:

1. Navigate to the Invoices List

2. Select and check the invoice you’d like to delete

3. Click on the 'delete' icon

Customer Screen:

1. Navigate to a particular customer

2. Click on the Invoices tab

3. Select and check the invoice you’d like to delete

4. Click on the 'delete' icon

Note: Deleting invoices is a permanent action and cannot be undo.