The The Order Comments Pro for Magento 2 allows customers to leave notes/comments before and after ordering and receive store administrators replies via email and under customer account at the frontend.
Notify both customers and admins for any additionals notes added to the order. Customers can add additionals notes and reply to the admin message under my account page. Order notes/comment historical available at both the admin side and frontend side (customer account). Insert order notes on email template to display on confirmation emails. An efficient tool for Magento 2 order communication
Check more details here : https://www.ulmod.com/ordernotes-for-magento-2.html