Prisma is an online private school, so you are not technically homeschooling in most areas when you enroll in Prisma. Because K-12 education is regulated at the state (and even local school district) level, we aren’t able to provide a singular response for what notification you may be required to provide or what steps you may need to take where you live. We’ve found that the majority of US states simply require a family to formally withdraw their child from public school—typically by filling out a form that can be obtained either online and/or at your local public school where you state the reason for not attending public school as attending private school instead.
A minority of US states classify students who attend an online private school not specifically based in the student’s state of residence as homeschooled. To our present knowledge, CA, LA, MA, MD, NY, PA, and WI operate this way. If you live in one of those US states, you can reach out to your local district to learn how to homeschool in your local area. If you live outside of the US, depending upon your home country of residence, your child may need to take locally required exams, which they'd be aware of in advance through Prisma's LaunchPad future planning program.
You can also read about homeschooling in your US state here or in your country here.