Hi,
Depends on the firm, could be:
1) Nearly fully automated (Big 4)
2) Automated with additional human review at 2nd stage screening (MBB, T2)
3) Purely human (Boutiques typically)
In terms of keywords, you'd want to use action verbs + description of the impact + potential skills developped.
Obviously IT systems would also filter by schools (target or not) & previous work experience, but that would show up on any CV by definition