What is a custom value ?

A custom value is a field that you can add at any moment. 

Generally, they are Id for : 

• promotions
• external tools such as CRM
• third-party applications

This type of field is displayed on the last tab of each dealer page in the backoffice :

Here are some articles that can interest you : 

• Add a field in DLU : manage custom value
• Add a field in an import/export file : exemple with custom value