try adding position-fixed to your div content, and declare col size, like this example.
I add a class .content-side with a margin to separe your columns.
.content-side{
margin-left: 30%;
}<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<meta name="csrf-token" content="6cVeUL8545aLqj1Fo8zZCGwhxzbZP5bsS4oPK5cG">
<link rel="stylesheet" href="style.css">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.12.0-2/css/all.min.css">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.min.css">
<title>Home | Larapi</title>
</head>
<body>
<div class="container-fluid d-flex justify-content-around">
<div class="row mx-0">
<div class="position-fixed col-md-3 col-sm-3 bg-dark text-light vh-100">
<h4 class="my-4 mx-3">
<a href="#" class="text-decoration-none">
<i class="fab fa-laravel text-light"></i>
<span class="text-light">Larapi</span>
</a>
</h4>
<h6 class="small text-uppercase mx-3">Models</h6>
<ul class="list-unstyled">
<li>
<a href="#" class="btn btn-block btn-primary text-left pr-3">
<i class="fas fa-fw fa-cog"></i>
Model
</a>
</li>
<li>
<a href="#" class="btn btn-block btn-link text-left text-light text-decoration-none pr-3">
<i class="fas fa-fw fa-cog"></i>
Model Name
</a>
</li>
</ul>
<h6 class="small text-uppercase mx-3">Admin</h6>
<ul class="list-unstyled">
<li>
<a href="#" class="btn btn-block btn-link text-left text-light text-decoration-none pr-3">
<i class="fas fa-fw fa-cog"></i>
Models
</a>
</li>
<li>
<a href="#" class="btn btn-block btn-link text-left text-light text-decoration-none pr-3">
<i class="fas fa-fw fa-cog"></i>
Files
</a>
</li>
<li>
<a href="http://larapi.test/logout" class="btn btn-block btn-link text-left text-light text-decoration-none pr-3">
<i class="fas fa-fw fa-sign-out-alt"></i>
Logout
</a>
</li>
</ul>
</div>
<div class="col-md-8 col-sm-8 content-side">
<div class="p-4">
<h1 class="mb-3">Home</h1>
<p>You are logged in!</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Tenetur, vel, veritatis! Ad, beatae consequatur cum cumque et exercitationem fuga laudantium nisi, nulla numquam odio omnis qui quod, similique sit vel?</p>
<br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
<br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
<br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
<br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Tenetur, vel, veritatis! Ad, beatae consequatur cum cumque et exercitationem fuga laudantium nisi, nulla numquam odio omnis qui quod, similique sit vel?</p>
</div>
</div>
</div>
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.5.0/js/bootstrap.bundle.min.js"></script>
</body>
</html>