Passing information to an Form submit

I had asked a poorly crafted question. I would like to pass an information through a form submit, this information would be standard eg:

  

Password = 123

This information would not appear to the user would be broadcast in the background for me to do a post.

I have some inputs, for example:

<div class="row" style="border:none!important;">
    <div class="form-group col-sm-6 col-xs-6 inline-input">
        <div class="input-group col-sm-12 col-xs-12">
            <div class="input-group-addon"><span class="elegant icon_phone"></span></div>
            <input type="text" class="form-control mask-phone" id="telefone-cadastro" name="telefone" placeholder="Telefone" required>
        </div>
    </div>
</div>

What I need is to pass an information as if it were an input but I would already set the value it was would have at the time of the submit.