Which of the following tags is essential for creating an interactive form interface?

The essential element for creating an interactive form interface is the form tag. This specific tag is vital because it establishes a boundary for input elements that allow users to submit data. The form tag encloses various input elements such as text fields, radio buttons, checkboxes, and submit buttons, enabling the capture of user information and the submission of data to a server for processing.

Without the form tag, these interactive elements would not function correctly as a cohesive unit. It defines the structure necessary for user interactions to be meaningful and operational, making it the cornerstone of any form-based interface in HTML.

The other tags mentioned, while useful in their contexts, do not directly contribute to the creation of an interactive form interface. The link tag is primarily used for creating hyperlinks; the image tag is for embedding images; and the header tag is used for defining headings in a document, none of which support the functionality and purpose of a form.