Creating a notification for all project managers when there is a new data inserted into the inventory?

Question

I need to automatically send a notification for every project managers after inserting a new data into the inventory, to notify them that there's a new item in the warehouse. Im new to django programming and i'm not familiar with using signals.

Models.py

class Item(models.Model):

ItemName = models.CharField(max_length=255, blank=True, null=True)
Quantity = models.IntegerField(null=True, default=1,
    validators=[ 
        MaxValueValidator(100),
        MinValueValidator(0)
    ])
ModelNum = models.CharField(max_length=255, blank=True, null=True)
Category = models.ForeignKey(Category,on_delete=models.CASCADE, null=True)
date_created = models.DateTimeField(auto_now_add=True)
last_modified = models.DateTimeField(auto_now=True)
is_draft = models.BooleanField(default=True)
reorder_level = models.IntegerField(blank=True,  default=10,
    validators=[
        MaxValueValidator(100),
        MinValueValidator(1)
    ])

class Meta: 
    verbose_name_plural = 'Item'

def __str__(self):
    return f'{self.ItemName}'



class Notifications(models.Model):

 id=models.AutoField(primary_key=True)
 sent_to = models.ManyToManyField(CustomUser)
 message = models.TextField(null=True)
 message_reply = models.TextField(null=True)
 created_at=models.DateTimeField(auto_now_add=True)
 updated_at=models.DateTimeField(auto_now=True)

Views.py

def inventory(request):
items = Item.objects.all()

if request.method == 'POST':
    form = ItemForm(request.POST)
    if form.is_valid():
        form.save()
        ItemName = form.cleaned_data.get('ItemName')
        messages.success(request, f'{ItemName} has been successfully added.')
        return redirect('inventory')
else:
    form = ItemForm()

context = {

    'items' : items,
    'form' : form,
}

template_name ='inventory-admin/inventory.html'
return render(request, template_name, context)