Hey!

The big four accounting firms are Diloitte, PwC, EY and KPMG. These are the world's largest professional service networks and all of these offers internships to undergraduates. Internship period varies from 3/4 weeks to 3 months maximum. To secure internship in any of these, you must have good academic record/CGPA ( 3.5+ out of 4 or 8+ out of 10). Make a good profile at linkedIn, mention your achievements, positions of responsibility etc. Keep your resume updated and polished. If you are from tier 1 college then these companies must visit your college and you can have direct chance for internship there. But if not, then you must visit their website regularly and keep updated for the period when they open the internship links.

Thankyou