OneOfficeERP has several types of reports which can be customized as per the users' requirement.
If there is a custom report which needs to be deleted, it can be achieved by following steps. Please note that its applicable only for the Custom Reports, and not for the standard reports.
In the Awesome Bar, type and select "Report List" for an option.
The Report List will have all the standard and custom reports of your account. You can select Custom Report to be deleted from the list itself, and click on Delete icon in the Actions Menu.
Or you can open that report, and delete it from File menu.