How to hide a field on the mobile form

To hide a field on the mobile form, look for it's <li> tag. In that tag, you can add the "hidden" attribute. 

Before: 

<li>
    <div id="amigo_id" class="value-group">

        <label class="name">amigo_id</label>
        <span class="assignment">:</span>
        <input type="text" class="value"></input>

    </div>
</li>

After: 

<li hidden>
    <div id="amigo_id" class="value-group">

        <label class="name">amigo_id</label>
        <span class="assignment">:</span>
        <input type="text" class="value"></input>
    </div>
</li>