An interview is a two-way street. They are not only interviewing your for the job, but you are questioning them to see if you are a good fit for the company if you are offered the position. You need to understand if taking the job is worth other opportunity costs.
You should be able to ask questions at the end of your interview. You should be prepared with questions ahead of time. You can bring a notebook with the questions written down. Have some extra questions in case all of your questions are answered.
Be careful of the questions you select. Some employers may judge you on the questions you ask.
Make sure you research the company and position before you go on the interview. A company website and social media is a great place to start. Prioritize the questions you have to about three to five at the end of an interview.
You should never ask about salary and benefits issues until those subjects are raised by the employer.
Showing you are prepared and have done your research will help you stand out in the candidate pool.