Attach Lookup Table

On the File | File Editor tab, in the View group: Click Attach Lookup Table to attach a lookup table to the field you have selected.

(This option is also available in the Wireframe Attribute Editor.)

A Lookup table is a data entry tool that allows you to select from a list of valid entries. Any values that are entered via the keyboard can also be validated against the codes defined in the table.

When you click the ellipsis (...) button to the right of a field that has a Lookup table attached, a "lookup list" is displayed: