The noun “whatever” can mean “no matter what” or “anything” or “everything.”
Order whatever you want from the menu; price is no obstacle.
Whatever you do, don’t order the raw oysters; I got sick the last time I had them.
As an adjective, “whatever” means “of any kind.”
This new submersible pump can be used at whatever temperature may be required.
As an adverb, “whatever” means “in any case.”
There is no evidence whatever that this well tapped any hydrocarbons.
One of the modern adverbial uses of “whatever” is the one accompanied by your teen rolling his or her eyes when you make a request.
“I asked you to clean your room, son.”
Now, the phrase “what ever” is used to express a question about a period of time.
What ever became of that old drilling rig Exxon bought for training purposes?
If the sentence still makes sense without the word “ever,” you can usually use the two separate words “what ever.”