Can I Use A Regular Check For Direct Deposit?
In theory, you should be able to just provide a routing number and account number to your payroll department. The voided check isn't necessary, it just happens to have both numbers printed on it. So long as they copy that information properly, they'll be able to make the deposit.
Can I use a check for direct deposit?
Most employers will ask for a voided check to set up your direct deposit in addition to filling out a form. They ask for this because a check has all the information your employer needs to help ensure your paycheck is deposited in your account. If you don't already have checks, you can order checks online.
How to Void a Check to use to set up a Direct Deposit
Do I need a check to set up direct deposit?
You do not need a voided check to set up direct deposit. If you're reordering checks, setting up a direct deposit or an automatic payment or preparing a wire transfer, you'll probably be asked to provide an ABA routing number.
Direct Deposit FAQs - Bank of America