Customer fields are fields associated with the customer account. You can use them to store advanced info related to customers.
Customer fields are visible at Support > Customer > View, also customer fields can be seen at the Individual ticket page under the “Raised By” widget at the info icon.
Edit Customer fields
Customer Fields can be edited from Support > Customer > Edit or Individual ticket page under the “Raised By” widget at the info icon but you should have permission to do so.