<script type="text/javascript">
$(window).on('load',function(){
$('#myModal').modal('show');
});
</script>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Example of Auto Loading Bootstrap Modal on Page Load</title>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/css/bootstrap.min.css">
<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/js/bootstrap.min.js"></script>
<script>
$(document).ready(function(){
$("#myModal").modal('show');
});
</script>
</head>
<body>
<div id="myModal" class="modal fade">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title">Subscribe our Newsletter</h5>
<button type="button" class="close" data-dismiss="modal">×</button>
</div>
<div class="modal-body">
<p>Subscribe to our mailing list to get the latest updates straight in your inbox.</p>
<form>
<div class="form-group">
<input type="text" class="form-control" placeholder="Name">
</div>
<div class="form-group">
<input type="email" class="form-control" placeholder="Email Address">
</div>
<button type="submit" class="btn btn-primary">Subscribe</button>
</form>
</div>
</div>
</div>
</div>
</body>
</html>