We i can edit the htacces?

Hello i will paste this in my Htacces:
**DirectoryIndex index.php index.html index2.html

ErrorDocument 400 /fehler/404.html

ErrorDocument 401 /fehler/404.html

ErrorDocument 403 /fehler/404.html

ErrorDocument 404 /fehler/404.html

ErrorDocument 500 /fehler/404.html

ErrorDocument 503 /fehler/404.html**

We i can make this?
When i conectet with ftp and edit it it will message a error: Permissions Denied

Just create a new file in your website’s htdocs directory called .htaccess and paste the rules in it. You can’t edit the root .htaccess file but you can override it’s contents.

thanks