Oh that one is now working when I used this :

*    public function makeAdmin($userId){
    	$user = User::where('id',$userId)->first();*
			
			
			
    	$old_role = $user->role;
    	$name = $user->name;
    	
    	$user->update([
    		'role'=>'admin'
    	]);
    	session()->flash("success","Now {$name} role {$old_role} is updated to {$user['role']}");
    	return redirect(route('users.index'));

    }

But I am still confused why the route binding User $user not worked ?

Do you have use App\User; in the top of the file?

@ Jason Weiss , Yes I used that . Otherwise it would give me a error . But it don't give me any error . it works good but the data is not updating

The route parameter and the controller method parameter should match.

Change userId to user in the following route:

Route::post('users/{**userId**}/make-admin','UsersController@makeAdmin')->name('users.make-admin');