When you use Link to entry or List of entries Fields, the linked entries are identified by one or more fields. By default, the name is taken from the first field in that category, but you can use other fields and add punctuation or other characters to clarify the relationship.
To change how entries are named, go to the Field configuration for the link or list field, and go to Advanced options.
The drop-down menus allow you to choose which field or fields are used in the name. The spaces between the menus allow you to add spaces or punctuation (such as commas or parentheses) to separate the different fields.
You set up two categories, Person and Company. On the Person entries, there is a link to entry field called Employer that links to Company. Because some companies in your application have the same name, you want to use two fields from the Company category to identify them. Configure the Employer field, go to Advanced options and choose a second field (e.g. Location) and add parentheses around it so that each company is identified as, e.g. “Acme Inc (New York)”.