Here I've made a page as per the image you placed here. Check the Demo.
span {
font-size: 20px;
background: #fff;
position:absolute;
top: -20px;
right: 70px;
padding:4px;
}
p{
border-radius: 25px;
width: 250px;
height: 150px;
border:10px solid #000;
background-color:white;
position:relative;
padding-top:15px;
}
p:after{
position:absolute;
content: " ";
width:50px;
height:50px;
border-right:10px solid #000;
right:18px;
bottom:-55px;
}
p:last-child:after{border-right:0;}
/HTML code will be like this/
<div id="box">
<p><span>Title will come here</span>so far, I have a base, but I have no idea how to customly design the rectangle with dissapearing section on the border lines and another line going down, the way I want it like this:</p>
<p><span>Title will come here</span>so far, I have a base, but I have no idea how to customly design the rectangle with dissapearing section on the border lines and another line going down, the way I want it like this:</p>
<p>><span>Title will come here</span>so far, I have a base, but I have no idea how to customly design the rectangle with dissapearing section on the border lines and another line going down, the way I want it like this:</p>
</div>