2
<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <title>Example1</title>
        <style type="text/css">
            * {
                margin: 0;
                padding: 0;
                box-sizing: border-box;
            }
            
            body {
                
            }
            header {
                background-color: aqua;
                display: block;
                float: right;
                padding: 1em;
                width: 85%;
            }
            main {
                background-color: fuchsia;
                display: block;
                float: right;
                padding: 1em;
                width: 85%;
                height: 300px;
            }
            aside {
                background-color: firebrick;
                padding: 1em;
                width: 15%;
            }
            footer {
                background-color: chartreuse;
                clear: both;
                padding: 1em;
            }
        </style>
    </head>
    <body>
        <header>HEADER</header>
        <main>MAIN</main>
        <aside>ASIDE</aside>
        <footer>FOOTER</footer>
    </body>
</html>
Welcome to Stackoverflow! Please explain the problem better, and if possible include a example of code that reproduces what is happening, because your question is not noticeable. See Help Center How to Ask.
– Taisbevalle