The process of creating a simple To-Do list using HTML, CSS, and JavaScript is very sample. Let's start step by step:
<!DOCTYPE html>
<html>
<head>
    <title>To-Do List</title>
    <link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>
    <h1>To-Do List</h1>
    <input id="taskInput" type="text" placeholder="Enter a task">
    <button id="addTaskButton">Add Task</button>
    <ul id="taskList"></ul>
    <script src="script.js"></script>
</body>
</html>
body {
    font-family: Arial, sans-serif;
    margin: 20px;
}
h1 {
    text-align: center;
}
input[type="text"] {
    width: 300px;
    padding: 5px;
    margin-right: 10px;
}
button {
    padding: 5px 10px;
}
ul {
    list-style-type: none;
    padding: 0;
}
li {
    margin-bottom: 5px;
}
// Get references to the HTML elements
var taskInput = document.getElementById("taskInput");
var addTaskButton = document.getElementById("addTaskButton");
var taskList = document.getElementById("taskList");
// Add event listener to the "Add Task" button
addTaskButton.addEventListener("click", function() {
    var task = taskInput.value;
    if (task !== "") {
        // Create a new list item
        var listItem = document.createElement("li");
        listItem.innerHTML = task;
        // Add the list item to the task list
        taskList.appendChild(listItem);
        // Clear the input field
        taskInput.value = "";
    }
});
That's it! You've created a basic To-Do list using HTML, CSS, and JavaScript. You can now open the HTML file in a web browser and start adding tasks to your list.