How to Add a Custom Admin System Message in Magento 2
Magento uses notification messages to improve user experience. You can simply add any message using the Message Manager to notify users whether the result of an action is successful or not.
In this blog post we will cover one type of the notifications – Admin System Messages. This type of notifications will be shown in a pop-up block and will be present in the admin panel as a reminder for an admin user until a special condition is met. These notifications can vary from messages about invalidated indexes to vulnerability issues. Adding custom system messages can be helpful and we are going to show you how to do it in few simple steps.