you need model release forms when taking pictures of people, when they are visible within the shot.Whenever the person within the image is recognisable or identifiable.
They are a legal document between the photographer and the model you are shooting. A written form of permission to the photographer saying that they allowed to use the images how they want to/ whatever is specified within the document.
Model release forms can be used in as a form of defence in a lawsuit. It can be used in a civil liability lawsuit. It protects both the photographer and the person being photographed.
Model release forms should be signed by both photographer and model. If the person is under the age of 18 then a parent or guardian should sign. The forms should also be dated – either from signature or date when the image was taken.
I hereby assign full copyright of these photographs to the above-mentioned photographer (and the related representatives and assigns) together with the right of reproduction either wholly or in part.
The Photographer and licensees or assignees may have unrestricted use of these for whatever purpose, including advertising, with any retouching or alteration without restriction.
I agree that the above mentioned photographs and any reproductions shall be deemed to represent an imaginary person, and further agree that the Photographer or any person authorized by or acting on his or her behalf may use the above mentioned photographs or any reproductions of them for any advertising purposes or for the purpose of illustrating any wording, and agree that no such wording shall be considered to be attributed to me personally unless my name is used.