Can we start a code without typing the head?

Answer 1

you could do so for any (html) target (not only playgrounds) thanks to html permissivity... but if you open developers tools you will see a full valid (minimalistic) html document / tree ;)

Answer 2

https://stackoverflow.com/questions/5641997/is-it-necessary-to-write-head-body-and-html-tags#:~:text=Omitting%20the%20html%20%2C%20head%20%2C%20and,didn't%20define%20those%20elements.

Answer 3

As stated by visph Yes. But it is not recommend unless for testing purposes. Or else your code will not validate. And it will make it difficult to develop/design webpages properly.

https://validator.w3.org