Legally, employers have the right to perform a background check before hiring employees. The interviewer wants to hear from you if you have a criminal background and the circumstances. Then, the interviewer can decide if your criminal history is significant enough to warrant hiring you or not. If you have something that will show up in your background, be honest and explain what happened, what your sentence was, and what you learned from that experience. If you have no criminal history, explain to the interviewer that you have never been in trouble with the law, and there will be no issues in your background check.