validation in laravel?

Accepted
Active URL
After (Date)
Alpha
Alpha Dash
Alpha Numeric
Array
Before (Date)
Between
Boolean
Confirmed

Date
Date Format
Different
Digits
Digits Between
E-Mail
Exists (Database)
Image (File)
In
Integer
IP Address
JSON
Max
MIME Types(File)
Min
Not In
Numeric
Regular Expression
Required
Required If
Required Unless
Required With
Required With All
Required Without
Required Without All
Same
Size
String
Timezone
Unique (Database)
URL

@if (count($errors) > 0)
<div class = "alert alert-danger">
<ul>
@foreach ($errors->all() as $error)
<li>{{ $error }}</li>
@endforeach
</ul>
</div>
@endif

public function validateform(Request $request) {
print_r($request->all());
$this->validate($request,[
'name' => 'required|max:8|min:4',
'email' => 'required|email',
'mobile' => 'required|Numeric|max:10',
'gender' => 'required',
'hobbies' => 'required',
'message' => 'required|alphaNum|min:20'
'post' => 'required|unique:posts|max:255',
'title' => 'required|unique|max:255',
"amount" =>" required|regex:/^\d+(\.\d{1,2})?$/",
"amount" =>" required|regex:/^\d{1,13}(\.\d{1,4})?$/",
//'name' => 'required|alpha',
//'name' => 'required|alpha_spaces',
'name' => 'regex:/([A-Za-z])+/',
'email' => 'required|email',
'password' => 'required|alphaNum|max:20|min:4',
//'phone' => 'required|digits:10', // work fine
'phone' => 'required|numeric|digits:10|starts_with: 6,7,8,9'
//'phone' => 'required|numeric|between:9,11',
//'phone' => 'required|min:10|numeric',
//'phone' => 'required|regex:/(01)[0-9]{9}/',
//'phone' => 'required|regex:/^([0-9\s\-\+\(\)]*)$/|min:10' ]);
}

public function contact(Request $request)
{
$rules = [
'name' => 'required',
'email' => 'required|email',
'message' => 'required|min:5',
];

$this->validate($request, $rules);

// send contact details to email address

return back()->with("status", "Your message has been received, We'll get back to you shortly.");
}

<div class="form-group {{ $errors->has('name') ? 'has-error' : ''}}">
<label for="name" class="col-sm-3 control-label">Name: </label>
<div class="col-sm-6">
<input class="form-control" required="required" name="name" type="text" id="name">
{!! $errors->first('name', '<p class="help-block">:message</p>') !!}
</div>
</div>

<div class="col-md-8">
<!-- <form method="post" action="{{ url('/main/checklogin') }}"> -->
<form name="frm" action="{{url('emailsend')}}" method="post">
<!-- {{ csrf_field() }} -->
@csrf
<!-- <input type = "hidden" name = "_token" value = "<?php //echo csrf_token(); ?>">-->
<div class="form-group" {{ $errors->has('name') ? 'has-error' : ''}}>
<label>Name</label>
<input type="text" class="form-control" name="name" id="name" placeholder="Enter Name">
{!! $errors->first('name', '<p class="help-block" style="color:red;">:message</p>') !!}
</div>

<div class="form-group">
<label>Email</label> <input type="text" class="form-control" name="email" id="email"
placeholder="Enter Email">

{!! $errors->first('email', '<p class="help-block" style="color:red;">:message</p>') !!}
</div>
<div class="form-group">
<label>Mobile</label> <input type="text" class="form-control" name="mobile" id="mobile"
placeholder="Enter Mobile">
{!! $errors->first('mobile', '<p class="help-block" style="color:red;">:message</p>') !!}
</div>
<div class="form-group">
<label>Gender</label>
<input type="radio" name="gender" value="male">Male
<input type="radio" name="gender" value="female">Female
</div>
<input type="checkbox" name="hobbies[]" value="Musics">Musics
<input type="checkbox" name="hobbies[]" value="cricket">cricket
<input type="checkbox" name="hobbies[]" value="NET">NET
<input type="checkbox" name="hobbies[]" value="Sweeming">Sweeming


<div class="form-group">
<label for="exampleFormControlTextarea1">Message</label>
<textarea class="form-control" name="message"
id="message" rows="3"></textarea>
</div>





<button type="submit" class="btn btn-primary">Submit</button>

</form>
</div>

public function store(Request $request)
{
\Validator::extend('without_spaces', function($attr, $value){
return preg_match('/^\S*$/u', $value);
});

$request->validate([
'username' => 'required|without_spaces|unique:user_detail,username',
]);

return redirect()->back();
}

public function store(Request $request)
{
$request->validate([
'username' => 'required|regex:/^\S*$/u',
]);

return redirect()->back();
}