To make reliable, safe, and effective use of data outside the context of its collection, we require an adequate understanding of its meaning. In data-intensive science, as in many other applications of computing, this necessitates the association of each item of data with complex, detailed metadata. The most important, most useful piece of metadata is often a description of the form used in data acquisition. This paper discusses, with examples, the requirements for standard metamodels or languages for forms, sufficient for the automatic association of form data with a computable description of its semantics, and also for the automatic generation of form structures and completion workflows. It explains how form models in specific domains can be used to facilitate data sharing, and to improve data quality, and semantic interoperability.