The first Street Fighter 6 beta will go live on October 7th. To sign up, go to this page and click the "Apply for the Closed Beta Test" button. You need a CAPCOM ID to apply for the test. If you don’t have one, you can create it on the website.
You can apply for the Street Fighter 6 closed beta on the official website between September 15th and September 30th. Capcom will announce the selection after October 5th, 2022. The lucky ones will receive a notification email with more details. As mentioned earlier, the tests are scheduled to begin on October 7th. The first beta will last until October 10th.
https://www.streetfighter.com/6/cbt/en/
Edited