To sell to the US Govt you need a contract vehicle. There are Govt -wide contract vehicles such as the GSA schedule. There are also Dept/Agency specific vehicles. Generally, services and products are sold using separate vehicles. It's a long, involved process and requires an accounting system that meets govt procurements regulations.
Your best bet is to team up with a company that already sells to the US govt and learn how they do it.
Your best bet is to team up with a company that already sells to the US govt and learn how they do it.