Hi,

Internship is period of work experience offered by an organization and sometimes it is without pay. It is to gain experience and satisfy requirements of qualification. Internship is for a limited period of time from few weeks to months.
It is to get pratical knowledge of your field. In an internship you might work on a project or working along with some executives. You can even get a full time job position with an internship.
There are some responsibility for interns such as PowerPoint presentations, drafting reports, designing creatives, handling company's social media accounts,writing emails, talk to clients on the phone, scheduling events, etc. It depends on your organization and your skills.
Doing an internship can really help you to gain experience and knowledge, it even helps you to develop your soft skills. It will help to shape your career.

Hope this information helps.
Good luck!!!