Working with government agencies is different than dealing with customers. They have certain timelines for each procedure and ERPNext can help you to remember those important dates.
Example: HR needs to renew visa/work permit of employees.
Rule 1: The visa/work permit can be renewed for the last 30 days of the permit/visa
Rule 2: If an employee has visa less than a week than the application will not be accepted
Where the information comes ?
You need to know which form which field the information comes from and it should be in date form.
In this example my information comes from employee file and my targeted field is a custom field. You can find your field under setup/customization.