ok guys i am showing you where you should write html or css.
the best html writer is brakets in my mind and i think so. it has all the oppurtunity to write your code. it has all the shortcut feature. you just write brakets in google and download the software and install it. and you are ready to make your expected thing. you can run the program first.
<title>this is about where you write your code</title>
<h1>this is heading one</h1>
<h2>this is heading two</h2>
<h3>this is heading three</h3>
<h4>this is heading four</h4>
<h5>this is heading five</h5>
<h6>this is heading six</h6>
after write this program you open this file with firefox,google chrome,ie or any other browser. then you see the output of this program.its easy man.just try and be developer.
or if you dont like this you can any other editor. like notepad which is default in your pc. or notepad++,sublime text3 etc.