That's usually achieved with CSS. The "text-indent" attribute is what you're looking for.
In the CSS file:
Code:
p {
text-indent: 1.2em;
}
Then in the HTML file:
Code:
<head>
<title>My Html file</title>
<link href="../Styles/stylesheet.css" rel="stylesheet" type="text/css" />
</head>
The above html code sssumes you have created a style sheet named stylesheet.css in your ePub (right-click on the "Styles" folder in the Book Browser and select "Add Blank Stylesheet" if you don't have a style sheet yet. Just make sure the file name is the same as what goes in the <link> tag above).