Tag Cloud visualization limits?

Elastic Stack Kibana
1

I am storing a content field with text extracted from documents. It does not appear as an option in the tag cloud visualization definition. Why?

What are the conditions under which a field is an option in the tag cloud visualization definition?

thanks.

2

It will only work on a keyword field - https://www.elastic.co/guide/en/elasticsearch/reference/current/keyword.html

3

That makes sense. Thanks.