You have to be on this list to attend a USSSA World. For GSL have to play State and 2-3 other events.

For USSSA, must win a berth(in Indiana) and play State. You can not just play State and go to Worlds in men's C-D-E-Co-ed D-E. The Spring state does not count as the Main States. But, you can get a berth from State, if you played a qualifier.

https://engine.usssa.com/sports/GlobalWSEligible.asp?WTD=V&iSeason=30&Sport=17