The 504 Plan is a plan developed to ensure that a child who has a disability identified under the law and is attending an elementary or secondary educational institution receives accommodations that will ensure their academic success and access to the learning environment.
The Individuals with Disabilities Education Act (IDEA) entitles children to a free and appropriate public education (FAPE). FAPE is one of the important legal terms for you to understand. Free means that all eligible students will be educated at public expense. Appropriate refers to an education which is tailored to the individual's needs. Public refers to the right of those with disabilities to be educated in the public school system. Education indicates that the child will receive the services indicated in their Individualized Education Program (IEP).
Individualized Education Program The IEP is a written document that's developed for each public school child who is eligible for special education. The IEP is created through a team effort and reviewed at least once a year. Before an IEP can be written, your child must be eligible for special education. Strategies for Success
So what are the differences between 504 and IEPs? Subtle but important as this article states https://www.washington.edu/doit/what-difference-between-iep-and-504-plan
Not all students who have disabilities require specialized instruction. For students with disabilities who do require specialized instruction, the Individuals with Disabilities Education Act (IDEA) controls the procedural requirements, and an IEP is developed. The IDEA process is more involved than that of Section 504 of the Rehabilitation Act and requires documentation of measurable growth. For students with disabilities who do not require specialized instruction but need the assurance that they will receive equal access to public education and services, a document is created to outline their specific accessibility requirements. Students with 504 Plans do not require specialized instruction, but, like the IEP, a 504 Plan should be updated annually to ensure that the student is receiving the most effective accommodations for his/her specific circumstances.