Picklist asset security
Security permissions allow an administrator to control accessibility, ensuring that only the appropriate users have the ability to view, edit, or create a picklist.
As an example, you may want the majority of your users to only be able to view picklists, allowing them to be used in campaigns, segmentation and other areas of the application. Only granting users the View permission ensures users do not accidentally modify or delete the picklist, thereby impacting campaigns, segments and so on in which it is referenced (used).
You must have Customer Administrator privileges to be able to make these changes.