How can I remove file extension from a website address?
First, verify that the mod_rewrite module is installed. Then, be careful to understand how it works, many people get it backwards.
You don't hide URLs or extensions. What you do is create a NEW URL that directs to the old one, for example
The URL to put on your web site will be yoursite.example/play?m=asdf
or better yet
yoursite.example/asdf
Even though the directory asdf doesn't exist. Then with mod_rewrite installed you put this in .htaccess. Basically it says, if the requested URL is NOT a file and is NOT a directory, direct it to my script:
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /play.php [L]
Almost done - now you just have to write some stuff into your PHP script to parse out the new URL. You want to do this so that the OLD ones work too - what you do is maintain a system by which the variable is always exactly the same OR create a database table that correlates the "SEO friendly URL" with the product id. An example might be
/Some-Cool-Video (which equals product ID asdf)
The advantage to this? Search engines will index the keywords "Some Cool Video." asdf? Who's going to search for that?
I can't give you specifics of how to program this, but take the query string, strip off the end
yoursite.example/Some-Cool-Video
turns into "asdf"
Then set the m variable to m=asdf.
So both URLs will still go to the same product
yoursite.example/play.php?m=asdf
yoursite.example/Some-Cool-Video
mod_rewrite can do lots of other important stuff too, Google for it and get it activated on your server (it's probably already installed.)
Just add an .htaccess file to the root folder of your site (for example, /home/domains/domain.example/htdocs/) with the following content:
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.php -f
RewriteRule ^(.*)$ $1.php
More about how this works in these pages: mod_rewrite guide (introduction, using it), reference documentation