Many to many field with extra fields in Django REST Framework

I have two models: Purchase and Product, in the Purchase model I have some fields and among them a many to many referencing the Product, but for each product inserted in the purchase I need to add a status field, price and quantity and I have no idea how I could do this. Later I need to change these fields and I also need to have the option of adding more products, changing a product or excluding it from the purchase.

Purchase

 class Purchase(models.Model):
     id = models.UUIDField(primary_key=True, unique=True, default=uuid4, editable=False)
     created_at = models.DateTimeField(_("Created At"), default=timezone.now)
     request_date = models.DateField(_("Request Date"), default=date.today)
     obs = models.TextField(_("Observation"))
     status = models.CharField(_("Status"), choices=STATUS, default="Pending", max_length=8)
     products = models.ManyToManyField(Product, verbose_name=_("Products"))
     approval_date = models.DateField(_("Approval Date"), blank=True, null=True)`

Product

 class Product(models.Model):
     id = models.UUIDField(primary_key=True, unique=True, default=uuid4, editable=False)
     code = models.CharField(_("Code"), max_length=30)
     un = models.CharField(_("Measurement Unit"), max_length=30)
     description = models.TextField(_("Description"))`

I've tried to create a PurchaseProduct model but I couldn't make it work properly.

PurchaseProduct

 class PurchaseProduct(models.Model):
     purchase = models.ForeignKey(Purchase, on_delete=models.CASCADE)   
     product = models.ForeignKey(Product, on_delete=models.CASCADE)
     quantity = models.DecimalField(_("Quantity"), max_digits=10, decimal_places=2)
     price = models.DecimalField(_("Price"), max_digits=10, decimal_places=2)
     status = models.CharField(_("Status"), choices=STATUS, default="Pending", max_length=8)`

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