Unable to edit .htaccess file

I am trying to edit my htaccess file, but whenever I try to upload the file through ftp the upload fails. If I try and edit it through the cpanel file manager, I get the message “This file could not be saved”
Anyone able to help me with this? It is important for me to be able to edit this file.

“Your” .htaccess file is in the htdocs folder of your website. You cannot change the root .htaccess file but you can override any settings and add your own by creating a new .htaccess file in the htdocs folder of your domain.