HTML is designed for marking up text by adding tags such as <p> to create HTML elements. HTML tags begin with < and end with >. Tags often occur in pairs of opening and closing tags. Some tags such as <img> always occur alone. Those tags usually (but not required to) have trailing slash.
Tags can have attributes. For example, <a> tag has href attribute for defining link target. Similarly, <img> tag has src attribute for defining image source.