Why am I unable to delete an inactive client from the QBO client list?

Hello, Yogan.

I appreciate you joining us here in the Community. I'd be happy to provide some information.

QuickBooks provides the option to make your customers inactive. At this time, there isn't an option to completely delete them from the system. I can see how being able to do this would be beneficial for you. I recommend leaving feedback for our developers. Comments are viewed and considered as they create new features and updates for QuickBooks. 

If you have any other questions, feel free to reach back out here.