If you decided to remove Magento 2 Admin Email Notifications by Magefan, please follow the steps below, also you can contact our team for a free consultation in case you have any issues with Magefan's extension.
Remove Extension Files
Removing files instruction depends on a way Admin Email Notifications extension has been installed.
1. If you can find the extension files in the folder
app/code/Magefan/AdminNotifications
then remove this folder.
2. If the extension was installed via the composer and its files located in the folder
vendor/magefan/module-admin-notifications
then run composer CLI command to remove it
composer remove magefan/module-admin-notifications