As a Zoho partner, we don't have any back-door access to your CRM. The only way we can access your account is if you provide us with a user login and password directly.
If we're working on your CRM over a longer period, it's best practice to set up a dedicated user login for us, rather than sharing an existing team member's personal credentials. This keeps access clearly attributable, makes it easy to review exactly what changes were made and when, and means access can be removed cleanly the moment the engagement ends, without needing to change anyone else's password.