Edit in JSFiddle

$(function(){
  $('.btn').click(function(){
    $('.box ,.btn').toggleClass('show');
  })
});

<button class="btn">abrir caja</button>
<div class="box">
  <p>caja abierta presiona el boton para cerrar</p>
  
</div>

*{
  margin:0;
  padding:0;
}
.btn{
  position:fixed;
  border: solid thin #ccc;
  padding: 5px;
  top:85px;
  left:0;
  transition: all 1s ease;
}
.btn.show{
  left:200px;
}

.box{
  position:fixed;
  width:200px;
  height:200px;
  border:solid thin #ccc;
  text-align:center;
  background:blue;
  border-radius: 5px;
  left:-201px;
  transition: all 1s ease;
}

.box.show{
  left:0px
}