Template parameters indicate values for controlling content in documents based on a template. Use template parameters for optional regions or editable tag attributes, or to set values you want to pass to an attached document. For each parameter, you select a name, a data type, and a default value. Each parameter must have a unique name that is case sensitive. They must be one of five permitted data types: text, boolean, color, URL, or number.

Template parameters are passed to the document as instance parameters. In most cases, a template user can edit the parameter’s default value to customize what appears in a template-based document. In other cases, the template author might determine what appears in the document, based on the value of a template expression.