The Index field allows you to specify that a specific response will be saved to the Content Library.
When you add or configure an answer type in a project, you will see the Index field as part of the answer type configuration.
If you select Index, that specific response will be added to the Content Library after the answer is saved.
If you have specified a header, it will be included with the pair. This can be helpful when a question has more than one response associated with it and you want to save only one. For example, you could have one answer type with the header Response and one with the header Meets/Does Not Meet. You can save the Response answer to your library for future use by selecting Index. If you clear the Index checkbox for the Meets/Does Not Meet answer type, it will not be saved.
You can also select the Index checkbox when you are importing a file and mapping it.