Custom mail-tags from html fields

So, I got my form to ask for user’s ‘interest group’ and it adds them in mailchimp.. works great.. I did this by inserting custom html checkboxes.. Works great, but how do I send this custom results in the email I receive? Thanks!

<label>Interests</label>
    <label>
        <input name="GROUPINGS[19761][]" type="checkbox" value="Certification"><span>Certification</span>
    </label>
    <label>
        <input name="GROUPINGS[19761][]" type="checkbox" value="Regeneration"><span>Regeneration</span>
    </label>
    <label>
        <input name="GROUPINGS[19761][]" type="checkbox" value="Disease Reversal"><span>Disease Reversal</span>
    </label>
    <label>
        <input name="GROUPINGS[19761][]" type="checkbox" value="Prolotherapy"><span>Prolotherapy</span>
    </label>
    <label>
        <input name="GROUPINGS[19761][]" type="checkbox" value="Evaluation"><span>Evaluation</span>
    </label>
    <label>
        <input name="GROUPINGS[19761][]" type="checkbox" value="Retreats"><span>Retreats</span>
    </label>

https://www.ads-software.com/plugins/contact-form-7/