Basically they call you onsite. You have to code solution to a problem on your laptop in 1.5 hrs. Its a larger problem than your typical LC like encoders, queue job scheduler etc Complexity and ds/algo needed varies depending on level. They look for correct output, clean code, exception handling and class level design.
During machine coding round, focus on writing a working code which covers all the sample cases and then if you have time left work on cleaning your code in terms of class design and other stuff. Problem solving/data structures, design and hiring manager round are very standard.