If you can't work and earn at least 1220/month, you would likely be applying for SSI. You can start the preliminary application online. From there, you would need to make an appointment with SSA to complete the full application.
If a parent is on SSDI or SS retirement, you would apply as a Disabled Adult Child on their account.
realize, to qualify, you must be expected to be disabled AT LEAST A YEAR despite treatment, based on your previous questions, it looks like you have not adequately attempted to treat it yet. You can apply (to protect your disability start date) now, but expect to be rejected as they will assume you can be successfully treated within a year. You will have to appeal 1 or 2 times to get approved and that can take 1-5 years (a couple years is typical).