How to make DFFs read only , on the employment self service

Summary: WE have some DFFS which we have created in Personal Information module, which have to be made read only, only on ESS not anywhere else.

Content (required): How can I achieve this? We want these flex fields to be read only on employee self service.

Version (include the version you are using, if applicable): 21D

Code Snippet (add any code snippets that support your topic, if applicable):