It says in the docs
https://doc.laserfiche.com/laserfiche/en-us/content/admin-laserfiche-ai.htm?Highlight=smart%20chat
A user must have the Read entry access right for a document to use Smart Chat for that document. If a document contains redactions, responses from Smart Chat will use the redacted text, to ensure that protected information cannot be accidentally exposed. If you are solely asking Smart Chat questions about Laserfiche using Laserfiche educational resources, rather than about specific documents, it can be used by any user.
In addition to this though, how do you add the smart chat feature to their bar so they can access it when they are looking at the repository or a document? This icon: