Hi gagandeeps,
Business rule:
A business rule is a server-side script that runs when a record is inserted, updated, deleted, displayed or when a table is queried. A typical business rule might execute a script after a user updates an incident or escalates the priority of a change request.
Business Rules - ServiceNow Wiki
https://docs.servicenow.com/bundle/istanbul-servicenow-platform/page/script/business-rules/concept/c...
Script Include:
Create script includes to store JavaScript functions and classes for use by server scripts. Each script include defines either an object class or a function. Script includes run only when called by a server script.
https://docs.servicenow.com/bundle/geneva-servicenow-platform/page/script/server_scripting/concept/c...
Script Includes - ServiceNow Wiki
Please mark my solution correct or helpful, if applicable.
Thanks & Regards,
Satyapriya Biswal
