in
resources
layouts/backend/
main.blade.php
partials
sidebar
footer
<!doctype html>
<html lang="{{ app()->getLocale() }}">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Laravel</title>
</head>
<body>
<!-- Footer -->
@yield('partials.footer')
<!-- /footer -->
</body>
</html>
@extends('layouts.backend')
@section('footer')
<div class="footer text-muted">Hello</div>
@endsection
footer
Have a look at the Docs, the section about Blade is really good.
I think there are a few logical issues here. If you have a footer that you want to include in your backend/master template, then there's no need to extend the layout in your footer, simply include it in your master template. Here's an example:
layouts/backend/main.blade.php:
<!doctype html>
<html lang="{{ app()->getLocale() }}">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Laravel</title>
</head>
<body>
@yield('main')
<!-- Footer -->
@include('layouts.backend.partials.footer')
<!-- /footer -->
</body>
</html>
layouts/backend/partials/footer.blade.php:
<div class="footer text-muted">Hello</div>
Also, you might want to review your folder organisation, maybe you can go with something similar
views/layouts/backend.blade.php
views/layouts/frontend.blade.php
views/layouts/backend/footer.blade.php
views/layouts/backend/header.blade.php
This is just an idea, of course you can do the folder organisation as you prefer.