Do I need to return the customer name in the View orders?

No model Ordem add the relation with model Cliente as follows:

$this->belongsTo(Cliente::class,'cliente_id', 'id');

-muitos-laravel / 152108 # 152108 "> this link has the explanation of how to configure relationships

in your class code:

class Ordem extends Model
{   
    protected $fillable =['id','cliente_id','valor','data','problema',];

    public function produtos()
    {
        return $this->belongsToMany(produto::class, 'ordem_id');
    }
    public function servicos()
    {
        return $this->belongsToMany(servico::class,'ordem_id');
    }
    public function cliente()
    {
        return $this->belongsTo(Cliente::class,'cliente_id', 'id');
    }
}

At your controller load the relationship in advance:

$list_ordens = Ordem::with('cliente')->get();

in your class controller :

class OrdemController extends Controller
{    
    public function listaordens()
    {
       $list_ordens = Ordem::with('cliente')->get();    
       return view('ordem.listaordens',['ordens' => $list_ordens]);
    }
}

and lastly on View

@foreach($ordens as $o)
 <tr>
    <td> {{$o->cliente_id}} </td> 
    <td> {{$o->cliente->nome}} </td> 
    <td class="text-right"> {{($o->data)}} </td>
    <td class="text-center"> {{$o->problema}} </td>
    <td class="text-right"> {{$o->valor}} </td>
    <td class="text-center"> 

That is, you need to set the relationship of the back, as it was just configured Client to Order .

See:

• Save 1: 1 Relationship on Laravel 5.3
• One-to-many relationship problems for laravel
• How to use the hasmany relationship no laravel 5.2?
• Laravel / Eloquent - Inquiry on more of a table
• Laravel checkbox checked or not checked according to Database
• How to change the keyword of laravel's relationship