To find this feature, go to the Engagement section in Form or Portal, and then enable this:
You have the option to choose an Airtable field that will be used as the name of the commenter when adding a comment through miniExtensions. This is how the commenter's name will appear in Airtable.
This is how it looks like in the miniExtensions.
💡Note
Users cannot add a comment in the portal if login is disabled.