What should a user do if they want to notify users on a specific date?

The most effective way to notify users on a specific date within Smartsheet is to utilize the trigger that activates "When a date is reached." This option leverages Smartsheet's automation features, allowing users to set up an alert that automatically notifies specific individuals or groups when a designated date occurs. This ensures that the notification process is seamless and requires no manual intervention on the specified date, enhancing efficiency and ensuring timely communication.

The other choices, while they may seem relevant, do not inherently provide the same automatic capability. An alert action may not be tied to a specific date without additional configuration, and a manual notification requires active participation from the user, which is less convenient. Setting a calendar reminder can be useful for personal reminders but does not directly integrate with user notifications in the context of Smartsheet's collaboration features.