In short yes, you may need to allow employees time off to vote, and you may even need to pay them for it.
The specifics depend on state law. Most states do require some kind of time off. Two hours is the most common allowance, and generally the employer can require that the employee it at the beginning of the end of their work day. The amount of time employees must be allowed often depends on how much time they have before or after their shift while the polls are open.
To learn about the law in the state or states where you operate. Find out more from Vote411.org