Bootstrap 5 Navbar Forms are used to create the components like a search bar, or login within a navbar.
Bootstrap 5 Navbar Forms Classes: No special classes are used in Navbar Forms. You can customize the form using Navbar and Form classes
Syntax:
<nav class="navbar">
<form>
<input class="form-control" type="..." >
<button class="btn" type="...">...</button>
</form>
</nav>
Below example illustrate the Bootstrap 5 Navbar Forms:
Example 1: In this example, we will create a search bar in Navbar Forms:
<!DOCTYPE html>
<html>
<head>
<link href=
"https://cdn.jsdelivr.net/npm/bootstrap@5.0.2/dist/css/bootstrap.min.css"
rel="stylesheet"
integrity=
"sha384-EVSTQN3/azprG1Anm3QDgpJLIm9Nao0Yz1ztcQTwFspd3yD65VohhpuuCOmLASjC"
crossorigin="anonymous">
</head>
<body>
<div class="container text-center col-7">
<h1 class="text-success">
GeeksforGeeks
</h1>
<h2>Bootstrap 5 Navbar Forms</h2>
<nav class="navbar navbar-light bg-light">
<div class="container-fluid">
<form class="input-group">
<input type="search"
class="form-control"
placeholder="I am a Search Box">
<button type="submit"
class="btn btn-outline-danger" >
Search
</button>
</form>
</div>
</nav>
</div>
</body>
</html>
Output:

Example 2: In this example, we will use the Navbar form with other nav elements.
<!DOCTYPE html>
<html>
<head>
<link href=
"https://cdn.jsdelivr.net/npm/bootstrap@5.0.2/dist/css/bootstrap.min.css"
rel="stylesheet"
integrity=
"sha384-EVSTQN3/azprG1Anm3QDgpJLIm9Nao0Yz1ztcQTwFspd3yD65VohhpuuCOmLASjC"
crossorigin="anonymous">
</head>
<body>
<div class="container text-center col-7">
<h1 class="text-success">
GeeksforGeeks
</h1>
<h2>Bootstrap 5 Navbar Forms</h2>
<nav class="navbar navbar-light bg-light">
<div class="container-fluid">
<a class="navbar-brand">
GeeksforGeeks
</a>
<form class="d-flex">
<input type="search"
class="form-control "
placeholder="Enter email">
<span class="input-group-text">
@geeksforgeeks.org
</span>
<button class="btn btn-outline-success"
type="submit">
Search
</button>
</form>
</div>
</nav>
</div>
</body>
</html>
Output:

Reference: https://getbootstrap.com/docs/5.0/components/navbar/#forms