Users can chat with each other inside the Google Docs, Sheets, and Slides files they are working on together with classic Hangouts.
Administrators can turn off chat inside Docs, Sheets, and Slides by turning off classic Hangouts. See Choose a chat service for your organization.
Note: The classic Hangouts service is not available in Essentials edition. Chat is always turned off in Docs editors if you have an Essentials account.
Conditions that automatically turn off chat
Chat in Docs, Sheets, and Slides is automatically turned off for your users according to the applicable age in your country. Also, some chat history and sharing settings automatically disable chat in Docs, Sheets, and Slides. For example, chat is disabled when you: