If you install, update or delete your plugins and themes frequently, definitely you will not like to enter your FTP credentials every time for this process. You can insert this code into wp-config.php to force auto update for WordPress or plugins.
From the installation folder, the file is located at wordpress/wp-config.php
/** Setup Auto Update For WordPress */ define('FS_METHOD','direct');
With this ‘direct’ method setup, you will be able to update or upgrade your WordPress and plugins installations to newer versions without having to provide any FTP details. This method might not work with every hosting and it might cause security issues with poorly configured hosts.