basically, you apply to IBCCES, indicating which parks you plan on visiting. after you indicate your specific needs and share basic confirming info with them, you will receive a number.
you then contact the specific park.
Universal, will get back to you to discuss by phone pre visit. Note that many have reported here that they are quite disgruntled. Turns out even tho they did receive an IBCCES card; they weren’t approved for any accommodation at Universal that they were granted in the past. Others, were surprised when it was determined they were eligible for a higher level of assistance.
many are complaining here of the process changing. However, once you do receive an IBCCES card, it appears to be a simple process to recertify it each year.
https://accessibilitycard.org/
the disability thread on these boards has an extensive sticky on IBCCES and many other threads asking specific questions.