When you use Office setup 365 PowerShell to delete a user account, the account isn’t permanently deleted.
You can restore the deleted user account within 30 days.
Let’s check the process here that How to delete & Restore the user account in Office setup 365 PowerShell.
How to Block Access to Individual User Accounts?
Delete a User Account in office 365 Powershell:
Remove-MsolUser -UserPrincipalName <Account>
Restore a Deleted user Account within the 30 day in office 365 Powershell:
Restore-MsolUser -UserPrincipalName <Account>
Remove an Individual User Account in office 365 Powershell:
Remove-AzureADUser -ObjectID <Account>
For more details, visit : www.office.com/setup