In the Type drop-down, you can select an option to determine how you want default local items to be created and managed.
The Checklist Items option allows you to specify default local items directly on this page.
You can modify and style these items and headers exactly as you would when editing a checklist normally. The only exception is that you cannot assign default items to users, since assigned items must be associated with a specific issue.
available since 5.1.0
The Template option allows you to select a project-specific template, and thereby use the items that it contains as default local items. This can be useful if a Checklist custom field is only used in a single project, and you would prefer to let the project administrator take care of keeping the template and default local items up to date.