How can I make the field that I want visible under Field Search?

The following article uses the 'Family Date' field as an example, but it is applicable to all fields capable of performing field searches.

1. Navigate to Field Management > Field Security. Ensure that you select the user group to which the user belongs.
2. Choose the field to be permitted and click on 'Apply.' 

Next, under the 'Field Display Setting' tab:
 

1. Select the user group.
2. Choose the component 'field  search'.
3. Check the checkbox for 'Family Date' and click on 'Apply.' Screenshot attached for reference.

After completing these steps, the 'Family Date' will become visible under field search.