Template Elasticsearch about data

Elastic Stack Elasticsearch
4

But if i configure a field => index : not_analyze, What is mean ?

This was an older method of marking a field as a keyword, the new way is to
simply use the keyword type in the mapping.

Ok, but what i can do it ? My currently template is well configured for that ?
(string_as_keyword)

In your current template you are mapping the field as both text and keyword,
so instead of

"mapping": {
  "type": "text",
  "norms": false,
  "fields": {
    "keyword": {
      "type": "keyword",
      "ignore_above": 256
    }
  }
}

you could do

"mapping": {
   "type": "keyword"
}