Imagine a hypothetical service business that welcomes an initial enquiry without a supporting document. A visitor has read the relevant service page and written a useful description, but their brief file is on another device. They should be able to send that otherwise complete enquiry under the business’s agreed rule.
If the form offers an optional attachment, its label and surrounding explanation should make that choice clear. Someone who selects the wrong file needs an understandable way to remove it. If an optional attachment cannot be used, the agreed journey should let them continue without it while keeping the requirement they have written available.
Review the no-file route, removal of a selected file and the supported way to continue after a file problem. The recipient should be able to recognise an enquiry sent without supporting material and arrange a later exchange if useful. This illustrative buying decision sits within the whole website project; file handling itself is only included when selected in the scope.