The happy with its toy is this grammar correct?

No, "The happy with its toy" is not grammatically correct. Here's why:

* Missing a noun: You need a noun to describe what is happy. For example, "The dog is happy with its toy."

* Word order: The adjective "happy" should typically come before the noun it describes.

Here are some corrected examples:

* The dog is happy with its toy.

* The child is happy with its toy.

* The puppy is happy with its toy.