Remove #theme_wrappers Enteirly

I’m writing my first module. And in the form drupal adds form-item form-type- for every item.
I was looking for a solution and find out this solution from stackoverflow
Couldn’t understand much from api page
The answer works fine for one input item not for entire form.
So, if I don’t want any wrapper at all, how could I remove them?

Drupal version: