Как сделать дополнительное поле в Register?

<div class="register">
    Чанк: <strong>lgnRegisterFormTpl</strong>
    <div class="registerMessage">[[+error.message]]</div>
    
    <form class="form" action="[[~[[*id]]]]" method="post">
        <input type="hidden" name="nospam:blank" value="" />
        
        <label for="username">[[%register.username? &namespace=`login` &topic=`register`]]
            <span class="error">[[+error.username]]</span>
        </label>
        <input type="text" name="username:required:minLength=6" id="username" value="[[+username]]" />
        
        <label for="password">[[%register.password]]
            <span class="error">[[+error.password]]</span>
        </label>
        <input type="password" name="password:required:minLength=6" id="password" value="[[+password]]" />
        
        <label for="password_confirm">[[%register.password_confirm]]
            <span class="error">[[+error.password_confirm]]</span>
        </label>
        <input type="password" name="password_confirm:password_confirm=`password`" id="password_confirm" value="[[+password_confirm]]" />
        
        <label for="fullname">[[%register.fullname]]
            <span class="error">[[+error.fullname]]</span>
        </label>
        <input type="text" name="fullname:required" id="fullname" value="[[+fullname]]" />
        
        <label for="email">[[%register.email]]
            <span class="error">[[+error.email]]</span>
        </label>
        <input type="text" name="email:email" id="email" value="[[+email]]" />
        
        <br class="clear" />

        [[+register.recaptcha_html]]
        [[+error.recaptcha]]
        
        <div class="form-buttons">
            <input type="submit" name="login-register-btn" value="Register" />
        </div>
    </form>
</div>