To remove asking FTP details while install plugins from admin

3 ways :

1.Here’s how you can do it:

1. Locate your WordPress root diectory and find the “wp-config.php” file.
2. Edit the file and insert this somewhere in the middle as it’s own block, we normally put it after the mysql username/password block.
/*** FTP login settings ***/
define(‘FTP_HOST’, ‘localhost’);
define(‘FTP_USER’, ‘yourftpusername’);
define(‘FTP_PASS’, ‘yourftppassword’);

save and quit.
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2.The easiest way to do this is to find out what user apache is running as and change ownership of the entire WordPress directory to that user. For example, if apache is running as ‘httpd’, you could use the following commands on your WordPress installation directory:

# chown -R httpd: wordpress

Tip: In order to find out what user your instance of apache is running as, create a test script with the following content:

<?php echo(exec(“whoami”)); ?>

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3.enable suPhp