Currently I was looking for a job. I have done my Master's in Finance & Marketing. I have come across a payroll company that was offering me a job.But I just wanted to know what exactly a payroll company does and its roles & responsibilities.

With that said, beware of scams, there they want to send you a check, have you deposit it in your account and then pay people.

Assuming this is a real office, not a work at home issue,
Yes, they will have companies, that they handle normally work hours, pay, benefits, so it is lots of accounting work and files.