If you can't find you .htaccess file.. this is one probable reason

First don’t panic like I did.
Not finding the .htaccess file under your directory could mean a lot of things:

Your server is hiding it in order to protect it. You can try first revealing this file by “force showing hidden files” in your ftp client application (Filezilla – Cyberduck – etc..)

or..

Your simply connected to your server using the wrong address (yourdomainname.com instead of https://ftp.yourdomainname.com). Some ftp client applications have specific requirements when you first establish a connection with your server and might remove the .htaccess document if you are not following their connection protocols.

Of course, there are many other reasons, but I found them very important to check before going into creating your own .htaccess files and uploading them on your server.