How do you want your cash/withdrawal?
I need a twenty and two tens.
I assume that this is a bank employee speaking to a customer.
You can mix denominations to get the total amount of your withdrawal.
The ATM machines have a feature which allows you to choose the cash denominations that you wish.
The ATM machines can dispense your cash in various denominations to make up the total amount of your withdrawal.
Alternatively, if it is an ATM manufacturer speaking to a bank employee, you might say:
The/our ATM machines have a feature which allows the user to choose the cash denominations that they wish.