Mass Update is an application for Salesforce users, focusing primarily on updating data without using record Id, i.e. you can use (Email Id, First Name, Last Name, Phone, etc.) to update the records.
If the user has a CSV file of records and they wanted to update it to salesforce, but don’t have record Id available with them, then this app finds record Id automatically and updates records based on the criteria the user have selected.
Once the record updates complete the application will send an Email to the user’s email address with record update result.