Looking for sample Process Model or Expression Rule that will create user account from excel or csv file and a human interface to verify and approve or the account creation or set a default password, which will not be in the excel or csv file.

What you could do is create a PM that has a task for a user to upload the document, then call the smart service to import to the DB (it is in this plugin: https://community.appian.com/b/appmarket/posts/excel-tools), then let the user see the data and decide on which to approve via a form. The array of the ones that they approve can then MNI through create user (https://docs.appian.com/suite/help/20.4/Add_User_Smart_Service.html).

Hope that helps to get you started!