Upload filesize?

How can i change the upload file size of 2mb? I’ve installed plugin, which shows 250mb, but when i add the file, it says, that the this is bigger than the upload file size in php.ini… i’ve tryed to add php.ini in php-admin with the code from video of youtube, but that didn’t work. In the root i have php.ini which has 16M setted, and still, i’m allowed to upload only 2 mb. How to fix it? Thanks.