Because of security reasons, we recommend making use of your
installdir/apps/joomla/conf/htaccess.conf file. You should be able to put your contents inside that file in the proper directory tag.
If you prefer not to, you can modify
installdir/apps/joomla/conf/httpd-app.conf, and edit the following line:
It should be modified to this:
After that, restart your server and make sure your
.htaccess files are updated.