what file is required to be created in plugin folder in order to show all the post content of a CPT with the help of permalink

Your post type name is event so create a copy of your single.php then rename it as single-event.php and keep it together in the same folder with single.php.

Now you can edit single-event.php file to or display whatever you have in your event posts.

Again, copy and rename single.php file to single-event.php. it will serve as single page for event post type.

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