Hi @IniobongNkanga-8038,
Welcome to the Microsoft Q&A platform!
According to the official documentation, the -PermanentlyDelete parameter is available only in the cloud-based service and applies to Exchange online. However, the official documentation also states that this switch works only on mail users that have already been deleted, but are still recoverable (known as soft-deleted mail-users).
So, before using its parameters, make sure that your situation complies with these regulations.
Please feel free to contact me if you have any queries.
Best,
Jake Zhang