The voucher program hands parents the money the schools would have gotten for having their child enrolled and lets them spend it on a private school with an agenda or a homeschooling program with an agenda instead.
Literally it exists entirely to take money that should have gone to the public school system and letting all the rich and white families siphon it off to totally not segregated private school classrooms and totally not creationist and quiverfull homeschool programs.
If ya don't believe me just look at the rate of adoption of these kinds of programs and enrollment of rich and white kids in these kinds of programs pre and post Brown V Board.
These systems were concocted by segregationists for segregationists to maintain educational segregation and inequality.