Internships are a great way to gain work experience in your field of interest before you graduate.
Many internships are non-credited, non-academic experiences, intended to allow you to apply the knowledge you have gained during your academic experience. Some internships allow you to earn academic credit. For these, you must work closely with a professor who directs an academic component of the internship that has been agreed upon and planned in advance of the experience.
As a junior or senior Sociology major, you could arrange to register for SOC 792, Research Internship, or SOC 793, Internship, if you would like to receive academic credit for your internship, and it is related to your major.
Your first step would be to discuss your internship interests with your faculty advisor or a Sociology faculty member.