You’re mixing Filament v3 form API with Filament v4 “Schemas”.
In v4, Filament injects a `Filament\Schemas\Schema` into `form()`, not `Filament\Forms\Form`. That’s why your page is getting:

> Argument #1 ($form) must be of type Filament\Forms\Form, Filament\Schemas\Schema given

### Fix (swap to Schemas API)

Update your page to accept/return `Schema`, and build **components()** instead of **schema()** at the top level. Also swap `Forms\Get|Set` for the Schemas utilities.

```php
<?php

namespace App\Filament\Clusters\Helpdesk\Pages;

use Filament\Actions\Action;
// Schemas (v4)
use Filament\Schemas\Schema;
use Filament\Schemas\Components\Wizard;
use Filament\Schemas\Components\Wizard\Step;
use Filament\Schemas\Components\Utilities\Get;
use Filament\Schemas\Components\Utilities\Set;

// Form fields (still from Forms)
use Filament\Forms\Components\Select;
use Filament\Forms\Components\TextInput;
use Filament\Forms\Components\FileUpload;
use Filament\Forms\Components\Textarea;

use Illuminate\Support\Str;
use App\Models\TicketCategory;
use App\Models\DonVi;

class TicketManager extends ... // your base class
{
    public function form(Schema $schema): Schema
    {
        return $schema
            ->components([
                Wizard::make([
                    Step::make('category')
                        ->label('Loại hỗ trợ')
                        ->description('Chọn loại sự cố')
                        ->schema([
                            Select::make('ticket_category_id')
                                ->label('Loại sự cố')
                                ->options(TicketCategory::pluck('name', 'id')->toArray())
                                ->required()
                                ->live()
                                ->afterStateUpdated(function ($state, Set $set) {
                                    $set('code', 'TIC-' . strtoupper(Str::random(6)));
                                }),

                            TextInput::make('code')
                                ->label('Mã phiếu')
                                ->disabled()
                                ->dehydrated()
                                ->required(),

                            Select::make('department_id')
                                ->label('Đơn vị')
                                ->options(DonVi::pluck('name', 'id')->toArray())
                                ->searchable()
                                ->required(),
                        ])
                        ->columns(2),

                    Step::make('details')
                        ->label('Chi tiết')
                        ->description('Thông tin chi tiết')
                        ->schema(function (Get $get) {
                            if ($this->isVehicleCardCategory($get('ticket_category_id'))) {
                                return [
                                    TextInput::make('full_name')->label('Họ và tên')->required(),
                                    TextInput::make('employee_code')->label('Mã nhân sự')->required(),
                                    TextInput::make('email')->label('Email')->email()->required(),
                                    TextInput::make('phone')->label('Số điện thoại')->tel()->required(),
                                    TextInput::make('vehicle_type')->label('Loại xe')->required(),
                                    TextInput::make('vehicle_color')->label('Màu xe')->required(),
                                    TextInput::make('plate_number')->label('Biển số xe')->required(),
                                    FileUpload::make('id_card_image')
                                        ->label('Ảnh CCCD/CMND')
                                        ->image()
                                        ->directory('tickets/vehicle_cards')
                                        ->visibility('public'),
                                    FileUpload::make('vehicle_image')
                                        ->label('Ảnh xe')
                                        ->image()
                                        ->directory('tickets/vehicle_cards')
                                        ->visibility('public'),
                                    Textarea::make('note')->label('Ghi chú')->rows(3),
                                ];
                            }

                            return [
                                Textarea::make('description')
                                    ->label('Mô tả chi tiết')
                                    ->rows(6)
                                    ->required(),
                                FileUpload::make('attachments')
                                    ->label('Đính kèm hình ảnh')
                                    ->multiple()
                                    ->image()
                                    ->imagePreviewHeight('150')
                                    ->maxSize(2048)
                                    ->directory('tickets/attachments')
                                    ->visibility('public'),
                            ];
                        }),
                ])->submitAction(
                    Action::make('submit')
                        ->label('Gửi phiếu')
                        ->action('submit')
                        ->color('primary')
                ),
            ])
            ->statePath('data');
    }
}
```

Key changes:

* `public function form(Schema $schema): Schema` (v4) instead of `Form`.
* Use `$schema->components([...])` at the top level (inside, you still call `->schema([...])` on layout components like `Wizard` or `Step`).
* Use `Filament\Schemas\Components\Utilities\Get` / `Set` in callbacks.
* For `options()`, pass an array: `->pluck(...)->toArray()`.

Docs for the new Schemas approach and Wizard live here (handy for future pages): Filament 4 Schemas overview and Wizards. ([Filament][1])

If you’re actually on Filament v3, the other option is to revert your imports back to `Filament\Forms\Components\Wizard` and keep `Form $form`. But given your stack trace is passing `Filament\Schemas\Schema`, you’re clearly on v4, so the patch above is the right move. ([Filament][2])

Want me to scan the rest of the page for any other v3→v4 mismatches (namespaces, actions, uploads)?

[1]: https://filamentphp.com/docs/4.x/schemas/overview/ "Overview - Schemas - Filament"
[2]: https://filamentphp.com/docs/3.x/forms/layout/wizard?utm_source=chatgpt.com "Wizard - Forms"