taking an early withdrawal from account. they will charge 20%, but what about the 10% by the government? Is that mandatory?
The 20% federal tax withheld is just to help you not incur an underpayment penalty. It functions like the withholding on W-2 income. The 10% under early withdrawal penalty will be calculated on your return (when you enter your 1099-R) and added to your tax liability for the year.