To perform the requested action, WordPress needs to access your web server

by

if you want to skip this popup on the every action (like plugin or theme activation) you can go to wp-config.php file and paste the code

define('FS_METHOD','direct');
define("FTP_HOST", "<server>");//for eg.localhost
define("FTP_USER", "<wordpress admin username>");
define("FTP_PASS", "<wordpress admin password>");

It works for me please try.