Riot Games created Valorant, and it has its own service and website where you can download their games for their platform. Because Riot handles all of this, players don't need to go anywhere else after downloading the game. Will Valorant make its way to Steam? It is extremely unlikely.
For those who want to download Valorant, you can do so from the main website. Before doing so, you will need to have created a Riot Account. You can do this on this page or subscribe to an existing page that you have already created.
After setting up your Riot account, you can start playing Valorant once the download is complete, and you follow the step-by-step instruction guide through the installation process. Once the download is complete, you should have a shortcut to the game in your main desktop window. If you don't, you can freely find it in your files by searching for "Valorant."
At this time, Riot Games has not created a launcher for all of its games. It could happen in the future, and it hasn't brought its massively popular League of Legends game to other platforms or storefronts. Because of this, you'll likely be able to connect it to your Steam account or find it in your Steam library. Valorant will likely continue to live with a single icon on your desktop.
If Riot were to create a launcher in the future, Valorant and the other Riot games, League of Legends and Legends of Runterra, would likely be available from this location.