There are many agents and agencies out there. This is a good place to start. A few hints.

1. Look for what genre they want.
2. Look at the books they’ve represented.
3. Don’t worry if it takes some time for them to respond to a query.
4. Some will not respond if not interested. Set a deadline for yourself and cross them off the list if no response by then. (I go 6 months)
5. Be professional.