Get the content_type_id for the changed item on save in the post_save signal

post_save_content_type_id

from django.dispatch import receiver
from django.db.models.signals import post_save
from django.contrib.contenttypes.models import ContentType

@receiver(post_save)
def model_saved(sender, instance, signal, *args, **kwargs):
    
    app_label = sender._meta.app_label
    model_name = sender._meta.module_name    
    content_type = ContentType.objects.get(app_label=app_label, model=model_name)
    content_type_id = content_type.id
    # do something useful with the content_type_id