How to delete “anonymouse submit”

You can log into Dashboard of your site > Questions > Settings > permission then disables all the check of the anonymous user.

If you mean disables all check of last line, i did it. But i can do it just for questions and answers not for comments (when i save settings everything become default). https://imglink.ru/show-image.php?id=85e7b871d3265cb5919dc55d65f97e15

But if i desable questions and answers for anonymouse “anonymous submit” still be in form

Just disable the post column. I have checked on our demo and it works fine.
https://www.dropbox.com/s/eywt2kw8906vhm0/screencapture-localhost-8888-dw-purity-wp-admin-edit-php-1490329360782.png?dl=0