Inquire at the Community Involvement Center on campus. Contact a particular organization or corporation directly if you know you would like to do an internship with them. Search their web site, ask how you can apply for an internship or create one. The best situation is to do an internship during your last three years of study. To obtain academic credit for an internship you need to contact your major department to make the necessary arrangements.
Most internships offer some type of remuneration, either wages or a stipend.
Every organization and corporation will be different. There are some places that still do not pay for internship work. You will need to decide if you can afford to work for the experience and opportunities, without pay. Yes, you can create an internship tailored to your academic or career interests. The key factor is that the internship provides educational or career experience.