Can someone explain term_vectors vs index_options v2

I am confused by when to use term_vector or index_options in the mapping
definition. Google led me to:
https://groups.google.com/forum/#!searchin/elasticsearch/term_vector$20vs$20index_options/elasticsearch/3OsHn5w3H-E/bgFRLcdgqGQJ

But unfortunately - I don't understand those words when they are arranged
like that.

Specifically, will I choose one of those settings or the other, or
sometimes both?

When I have fields that I'm usually doing phrase searches on, should I set
one or both of those values? and to what?

What should I use when I want to use autocomplete? or highlighting?

Any help is appreciated - thanks!

--
You received this message because you are subscribed to the Google Groups "elasticsearch" group.
To unsubscribe from this group and stop receiving emails from it, send an email to elasticsearch+unsubscribe@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/elasticsearch/7afe3a96-eecf-4211-bc27-5aba1e8dd2c8%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.