Booz Allen Hamilton is an American consulting firm that works mostly for the US government, especially defence, intelligence and civil agencies. It's also the firm that the old Booz & Company split from in 2008; Booz & Company later became PwC's Strategy&.
The important bit for international students
A lot of Booz Allen's work needs a US security clearance, and clearance usually needs US citizenship. For most UK, Chinese, Indian and Nigerian students, that rules out most roles. If you were looking for the strategy firm with "Booz" in its history, you probably want Strategy& instead.
If you're a US citizen
It's a big employer of graduates in Washington DC and around the US, particularly for technology, data and analysis work.
- Show technical skills: data analysis, coding, cyber security.
- Show an interest in public service, because the clients are government agencies.
- Be ready for a clearance process that can take months.