The Localization metadata field is found under System Fields and can be set on forms for both cases and contacts:

The field's properties consist of the following:

Information field
Here you can optionally select an information field to be used for dynamic help text.
Information field text
Here you can optionally enter a help text to be displayed in the selected information field.
Label width
Here you specify the width of the label area.
Label
Here you specify the label, which is the text displayed as the heading/name of the field.
Name
The field's name (cannot be changed).
Tool tip
Here you can optionally enter a tooltip to be displayed when the user hovers over the field.
Map support