Your iPlum name is your Caller ID. You can change it in the iPlum app or online iPlum portal.
iPlum App Settings || My iPlum Account || Name (edit)
Login to iPlum portal. Accounts || Select Account || Profile & Permissions || Caller ID Name (edit)
Note: Most carriers would show both the caller name and phone number in the Caller ID but some receiving carriers may show only the caller number with city & state based on their internal policies.