HTML Form Action Attribute
The action attribute specifies the URL of the page to which the form data will be sent.
If the value of the action attribute is null or an empty string, the browser assumes the URL of the page where the form is currently located. That is, after submitting the form, the data does not go to another page. The data comes to this current page.
Example
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<h3>Login Form</h3>
<form action="login.php" method="post">
<label for="user-email">Email</label>
<input type="email" id="user-email" name="user-email">
<br><br>
<label for="user-pas">Password</label>
<input type="password" id="user-pas" name="user-pas">
<br><br>
<input type="submit" value="Login">
</form>
</body>
</html>