Wildcard search across multiple fields using RestHighLevelClient

I have documents like the following in my Elasticsearch index:

{
"id": 3,
"name": "Jon Loyens",
"age" : 33,
"address": "104, Hillside Avenue",
"city": "London"
"geo": {
"code": 44,
"country" : "UK"
}
}

Given a partial term like "on", I want to be able to get all the documents in the index which have any field containing "on". In the above example, both "name" and "city" have "on" in them and hence I would expect this document to be returned (and similarly any other document that contains "on" in any of the fields.)

Can someone lead me to the correct solution that will help me achieve this?

Also, I am using the RestHighLevelClient from Java in case it helps you.

Thanks for your help.