There are basically two ways by which you can align items to the center which are as follows:
<!DOCTYPE html>
<html>
<head>
<title>Align nav bar item into center</title>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous" />
<link rel="stylesheet" type="text/css" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" />
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css" />
<style>
.navbar-nav.navbar-center {
position: absolute;
left: 50%;
transform: translatex(-50%);
}
</style>
</head>
<body><br>
<!--NAVBAR STARTING-->
<nav class="navbar navbar-expand-sm navbar-light bg-light">
<div class="container">
<a class="navbar-brand text-success" href="#">
BAJARANGI SOFT
</a>
<button class="navbar-toggler" type="button"
data-toggle="collapse"
data-target="#navbarSupportedContent"
aria-controls="navbarSupportedContent"
aria-expanded="false"
aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse"
id="navbarSupportedContent">
<ul class=" nav navbar-nav navbar-center">
<li class="nav-item active">
<a class="nav-link"
href="#">
Home
<span class="sr-only">
(current)
</span>
</a>
</li>
<li class="nav-item">
<a class="nav-link"
href="#">
About
</a>
</li>
<li class="nav-item">
<a class="nav-link"
href="#">
About
</a>
</li>
</ul>
</div>
</div>
</nav>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<title>Align nav bar item into center</title>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous" />
<link rel="stylesheet" type="text/css" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" />
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css" />
</head>
<body style="background-color: #de5b5b">
<nav class="navbar navbar-expand-sm navbar-light bg-light">
<div class="container">
<a class="navbar-brand text-success" href="#">
Bajarangi Soft
</a>
<button class="navbar-toggler" type="button"
data-toggle="collapse"
data-target="#navbarSupportedContent"
aria-controls="navbarSupportedContent"
aria-expanded="false"
aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse"></div>
<div class="collapse navbar-collapse"
id="navbarSupportedContent">
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link"
href="#">
Home
<span class="sr-only">
(current)
</span>
</a>
</li>
<li class="nav-item">
<a class="nav-link"
href="#">
About
</a>
</li>
<li class="nav-item">
<a class="nav-link"
href="#">
Contact
</a>
</li>
</ul>
</div>
</div>
</nav>
</body>
</html>