I want to add a notification in the admin interface that tells users “plugin activated” for example, but I don’t know which action hook should I use, knowing that I want the message to display not just in the dashboard page, but in all the admin interface pages, like Dashboard, Appearance, Settings…etc, and I want the message to be under the first title of that page, like for example, if we are under Dashboard page, my plugin message should be under the title “Dashboard”, if we are under Plugins page, my plugin message should be under the title “Plugins”…etc

I have a fully developped plugin, its settings are in the main plugin’s settings page (Admin interface). Actually, I want any user to be able to edit his/her website design using this plugin in the WP Customizer. So the idea is to add an option in my plugin so it can be displayed in the WP Customizer, and add the design options editing.

I have an issue with my plugin’s description,
When I go to the Admin interface in WordPress -> then Plugins -> then Installed Plugins, I see all the other plugin’s description, except the one that I developed for this new plugin,