A form is a document with spaces (also named fields or placeholders) in which to write or select, for a series of documents with similar contents. The documents usually have the printed parts in common, except, possibly, for a serial number.
Forms, when completed, may be a statement, a request, an order, etc.; a check may be a form. Also there are forms for taxes; filling one in is a duty to have determined how much tax one owes, and/or the form is a request for a refund. See also Tax return.
Forms may be filled out in duplicate (or triplicate, meaning three times) when the information gathered on the form needs to be distributed to several departments within an organization. This can be done using carbon paper.
Forms have existed for a significant amount of time, with historians of law having discovered preprinted legal forms from the early 19th century that greatly simplified the task of drafting complaints and various other legal pleadings.
Advantages of forms include the following:
A form on a computer allows for conveniently typing in the variable parts (the input data).
A blank form is like a usual document, with some outlined parts with spaces. Blank forms are generally not copyrightable in the US.
Part of the document that never changes. Usually a frame with title and textual instructions.
Boxes or spaces where the user can write or type to fill in the form.