Hey @Mohammad_Arab , Welcome to the Local Community Forums!
Because Local has to work on both *nix systems as well as Windows, it uses a template file that’s re-compiled everytime a site is restarted.
This topic seems similar to what you’re asking: Local is filling up the hard disk in my MAC - #2 by ben.turner
But basically, double-check that you are editing the .hbs file and not the compiled configuration file. By default, PHP’s configuration for a site is located at:
~/Local Sites/sitename/conf/php/php.ini.hbs
Can you try editing that .hbs file, restarting the site, and see if that gets things working for you?