How does the FOIA extend to the public the right to access information in the possession of a public body?

1.    Mandatory release:
Every public authority is required to publish an Annual Statement under the FOIA . This statement gives an outline of the operations of the organization and the information which it holds.
2.    Proactive release:
Agencies are encouraged to make available as much government information as possible. This can be released through their websites, brochures, publications, press releases, etc.
3.    Informal request:
Nothing prevents the public from informally requesting specific information from public authorities and from agencies responding to such requests. But in circumstances where the information is not already in the public domain the agencies can insist that applicants complete a formal request form.
4.    Formal application:
If you have not been able to get the information you need in any other way, you can formally request specific information through the FOIA.