Bonjour Ayas. You'll need a work visa and I found what looks like a good article on getting internships in the U.S. for international students. https://www.gooverseas.com/blog/complete-guide-to-internships-in-united-states-for-international-students
I spoke with our associate director of internships and she told me that AT&T doesn't do sponsorships for our internship program. But I'm sure other U.S. companies do. She also told me that most major corporations (including AT&T) begin recruiting for interns in the months of September, October, and November and make offers in December and January. That's not to say that some don't hire later, but that's generally the timeframe. So it's good for you to do your research now to be prepared for intern jobs posting late in the year.
I hope this helps!