Hello!
I was able to do that!
I created the custom.css file at:
/opt/zammad/app/assets/stylesheets/custom
put this content in
a[data-type=“internal”], a[data-type=“public”],{
display: none;
}
ran these commands
$ chown zammad:zammad custom.css
$ zammad run rake assets:precompile
$ systemctl restart zammad-web
Now those buttons are hidden