Data policies are used to define rules that govern the creation, modification, and deletion of data in ServiceNow. These policies can be used to ensure data consistency by enforcing data quality standards and preventing invalid or inaccurate data from being imported.
References:
* ServiceNow Product Documentation: Data policies overview - https://docs.servicenow.com/bundle
/vancouver-platform-administration/page/administer/field-administration/concept/c_DataPolicy.html

A trigger is an activity that, once specified, automatically initiates a flow1. A trigger specifies the conditions that start running the flow, such as creating a record in a specified table, receiving an inbound email, or reaching an SLA target1.
References
* Flow trigger types - Product Documentation: San Diego - ServiceNow1

Explanation
To rearrange the columns on a list, users can right click on any column header and select Configure > List Layout from the context menu2. This will open a dialog box where users can select the available fields and move them to the selected list using the arrow buttons2. Users can also drag and drop the fields to change the order of the columns2.
References
How To Configure List and Form Layouts | by ServiceNow Scholar - Medium2