Add an additional, optional field to the Contact Form element to collect contact phone number. This should also have an option to make it a required field.

This is essential sales contact information for my business, which sells high value training packages, rather than just on-demand courses. Having the form submitted to my email address allows me to reply in a timely manner. Having to do an extra step in my sales funnel - having to email them back to request this info - is very inefficient!