Yes, you can!

It's true that Yahoo! Mail now automatically saves an email you're working on as a draft, in case you happen to lose power or lose your connection to the internet. It's also true that Yahoo! Mail removes an auto-saved draft from your Drafts folder when you send it. But you can block that behavior and both Send and Save a message as a draft.

Here's how:

Hold down the shift button:

• when you click Send, or
• when you hold down Ctrl and press Enter (the keyboard shortcut for sending).

That's:

Shift + Send

Or...

Shift + Ctrl + Enter (on your keyboard).