In case of a Bundle Membership, apart from the Member details, the company details has to be captured. This is the reason, once the bundle membership is enabled for a plan, a “Bundle form” is provided.
Please build this dynamic “Bundle Membership Form” by adding the various form fields. Just to add here, by default, there is always a Company Name text box. You can add other form fields. No need to capture the members details here as that will be available as part of the membership form.