Hi sushant,
Data integration rules are provided by a data service to control how the service updates your Salesforce records. Rules tell the data service how to find records to update and which updates to make. Rules also control how updates affect other features, such as triggers and workflow rules.
for more info go to :-https://help.salesforce.com/articleView?id=data_dot_com_clean_admin_set_up_clean_rules.htm&language=en_US&type=0