A rider is an attachment to a document which supplements or changes it. It is commonly used in insurance policies to add coverage, such as additional coverage for an engagement ring not covered under the general terms of a homeowner's policy. In the context of lawmaking, it is an amendment tacked onto a bill which in mostly unrelated to the main purpose of the legislation, but is a tactic used to get the amendment passed if the main bill is favored for passage.
This form is a rider to a lease agreement. This form is a generic example that may be referred to when preparing such a form for your particular state. It is for illustrative purposes only. Local laws should be consulted to determine any specific requirements for such a form in a particular jurisdiction.