How do you punctuate hello john?

The correct punctuation for "hello john" depends on the context:

1. As a greeting:

* Hello, John. (A comma is used after the greeting and before the name)

2. As a statement:

* Hello John. (A period is used at the end of the sentence)

3. As an exclamation:

* Hello, John! (An exclamation mark is used at the end of the sentence)

The most common punctuation is likely "Hello, John." as it is a friendly greeting.