So in my order is_curbside_pickup is true and the customer enters the pickup details after they have arrived at the location. So after the customer enters the details after arriving at the location, are the details shown as a notification or something in the dashboard?
Unfortunately, the details will need to be entered prior to the customer arriving. There isn’t currently a way to allow the customer to enter details after they arrive and update the order. We’re constantly working to improve our features based on feedback like this, so I’ll be sure to share your request to the API product team. 
I thought of updating the details using the update order API and the update was done. What I am wondering is if the store is notified in some way of the update?
What fields are you looking to update after the order is paid for? Also there isn’t a notification that the seller would see if the order fulfillment is programmatically updated at this time.