Checkbox Field in Contact Form 7
Allow multi-select options with `[checkbox]` / `[checkbox*]`.
Allow multi-select options with `[checkbox]` / `[checkbox*]`.
Accept uploads with `[file]` / `[file*]` and limit types/sizes.
Pass context with `[hidden]` tags (campaign, page URL, product ID).
Accept numeric input with `[number]` / `[number*]` and min/max options.