<form enctype="multipart/form-data" action="/fu.php" method="POST">
<input name="userfile" accept="image/*" type="file" />
<input type="submit" value=" Send ">
</form>

#btn {
    padding-left: 5px;
    font-size: 14px;
    border: 1px solid #333;
    background: #ccc;
    color: #161;
    width: 70px;
    height: 19px;
}

<form enctype="multipart/form-data" action="/fu.php" method="POST">
<div id="btn">
<label for="files">Мой текст</label>
</div>
<input id="files" style="visibility:hidden;" name="userfile" accept="image/*" type="file">
<input type="submit" value=" Send ">
</form>